Out past the last subdivision, Middle Tennessee turns into ridges, tobacco barns and pasture — and how much of it you can buy is set by county zoning, not by price. In unincorporated Sumner County, the Rural Residential district requires 40,000 square feet, a little under an acre; Agricultural Reserve requires 653,400 square feet, or 15 acres. In unincorporated Williamson County, the RP-5 and RD-5 rural districts require 5 acres in a traditional subdivision, RP-1 and RD-1 one acre in a traditional subdivision (10,000 square feet in a conservation subdivision, at the same one unit per acre). Inside a city's limits, the city's rules apply instead of the county's. And in Sumner's Rural Residential and Rural Preservation districts, public water that is unavailable or below the provider's minimum, no hydrant within 500 feet, or a development along a state or county road under 18 feet wide pushes the floor to 5 acres.
What are people actually buying the land for?
Almost nobody wants "land" in the abstract. Underneath the request is usually something specific: a shop or garage big enough to work in, a barn, room for animals, or more distance between buildings.
Sumner County's resolution is unusually clear here. Where land meets the "Agricultural Land" criteria set by the Tennessee Comptroller's Greenbelt Manual and by the resolution itself, § 1103.T exempts "all barns, sheds, silos or other buildings used exclusively for agricultural purposes" from the bulk or yard requirements in every district, and requires no building permit. The same section adds that under Tenn. Code Ann. § 13-7-114, where land was in agricultural use when the resolution was adopted, zoning may not interfere with that use while it continues (revisions effective 12/08/2025).
A workshop not used exclusively for agriculture is an accessory structure, with height, setback and permit rules. The exemption is real, and narrower than it sounds.
What actually decides how much land you can buy?
Two things: whether the parcel is inside a city, and which zoning district it sits in.
County zoning governs unincorporated land only. Sumner's resolution applies "within Sumner County's unincorporated planning area" (§ 103), and Williamson's applies "to the development of all unincorporated land within the boundaries of Williamson County" (§ 1.04). So "how much land can I get in Franklin" and the same question about unincorporated Williamson County have different answers: a parcel just outside a city limit follows a different rulebook from the one across the road.
How much land does each county actually require?
Sumner County (unincorporated). From Table 1 of the Zoning Resolution, revisions effective 12/08/2025: Agricultural Reserve, 653,400 square feet (15 acres); Rural Preservation, 100,000 square feet, about 2.3 acres; Rural Residential, 40,000 square feet; Suburban Residential, 20,000 square feet. The provision most buyers miss is headed "Provision for Variable Lot Size and Adequate Infrastructure in the RR & RP Zones" — it applies in those two districts only. There, a lot may not be less than 5 acres (217,800 square feet) if water service is not available or does not meet the provider's minimum requirements; if the lot is not within 500 feet of a fire hydrant; or if it sits in a development along an existing state- or county-maintained roadway under 18 feet of pavement width and/or without two connections to a public roadway. Any one of the three sets the floor. Minor subdivisions are exempt from the hydrant and road parts where public water is available, with the district's own minimum still applying; so-called "family subdivisions" — the resolution's own term for land divided among relatives — are outside the provision entirely and are governed by the resolution's separate standards for them.
Williamson County (unincorporated). From Article 10 of the Zoning Ordinance, adopted May 14, 2012, effective January 1, 2013, and amended through January 12, 2026 per its own Appendix of Changes. The Voluntary Agricultural district requires 15 acres. The rural districts split at the interstate: Rural Preservation (RP-5, RP-1) west of I-65, Rural Development (RD-5, RD-1) east of it. RP-5 and RD-5 require 5 acres in a traditional subdivision, at one unit per 5 acres; RP-1 and RD-1 require 1 acre in a traditional subdivision and 10,000 square feet in a conservation subdivision, both capped at one unit per acre — Tables 10.02-4 and 10.02-5, with § 12.02(A) making conservation subdivisions eligible in both at a minimum of five lots on a 10-acre site. The ordinance also writes separate dimensional tables around individual crossroads communities — College Grove Village, Leiper's Fork Village, the Grassland Village character districts and the Triune Character Areas — each drawn from that community's Special Area Plan.
Wilson County (unincorporated). The county's Board of Zoning Appeals agenda of July 17, 2025 (retrieved and archived September 2, 2026) cites Article 5, Section 5.20 of the Zoning Ordinance for the Agricultural (A-1) district: for a dwelling not served by a public sewer system but served by a public water system, a minimum lot area of 80,000 square feet — about 1.8 acres — "however, a greater lot area may be required based on recommendations by the State of Tennessee Department of Environment and Conservation." Where dwellings are not on public sewer, the minimum lot width is 125 feet at the front building line. Both standards carry revision markers, so confirm the current text with the Wilson County Zoning Division.
Davidson County. Acreage exists inside Metro. The Metro Nashville Planning Department lists AR2a at a 2-acre minimum and AG at a 5-acre minimum, both "intended for uses that generally occur in rural areas," and RS80 at "a minimum 80,000 square foot lot."
Why does a five-acre district sometimes produce half-acre lots?
Because in Williamson County the density is capped, not the lot. In RP-5 and RD-5, a conservation subdivision may plat lots averaging three-quarters of an acre, with a half-acre floor — raised from a quarter acre on November 10, 2025 — and a 70-foot minimum width, while the development as a whole stays at one unit per 5 acres. The land is preserved in the aggregate; the lots are not. A footnote adds that any lot under three-quarters of an acre must sit internally within the development, surrounded by lots of at least three-quarters of an acre, or in a location where the homes on them will not be visible from adjacent properties or road rights-of-way.
"Five-acre zoning" on a map does not promise a five-acre yard. Read the plat, not the district label.
What decides whether you can build on it?
Usually the septic system. Any individual or property owner who wants a subsurface sewage disposal system installed — or a faulty existing one repaired — must get a Septic System Construction Permit from the Tennessee Department of Environment and Conservation, through its Division of Water Resources. The application asks for a rough sketch of property lines, house site, well and spring locations, driveway and utilities, and, where required, soils maps by a soil scientist. TDEC states the review "generally takes 10 days and must be completed within 45 days of the date the application was submitted."
One line on that page is easy to misread, so here it is scoped: on its list of active installers, TDEC notes that installer permits are valid statewide, and that its contract counties — Davidson and Williamson among them — may require an additional permit. That is the installer's permit, not the owner's.
Both county codes defer to the state. Sumner's resolution states that "depicted minimum lot sizes are dependent upon such lot meeting the requirements of the State of Tennessee for wastewater treatment," and Wilson's A-1 standard allows a greater lot area on TDEC's recommendation. The zoning minimum is a floor; soil raises it.
You can pre-screen soils on Web Soil Survey, the USDA Natural Resources Conservation Service's public map tool. It is not a permit or a site evaluation — it tells you whether a parcel is worth the trip. Once you own the ground, the build side of this — the certified soil evaluation, the well, road access and county permit fees — is laid out in our guide to building on your own lot.
What is greenbelt, and why does it matter on an acreage purchase?
Tennessee's Agricultural, Forest and Open Space Land Act of 1976 — Tenn. Code Ann. §§ 67-5-1001 through 1050, commonly known as "greenbelt" — lets qualifying land be assessed on its present use rather than its highest and best use. Per the Comptroller's Greenbelt Manual, approved by the State Board of Equalization in October 2023, agricultural land must be at least 15 acres, including woodlands and wastelands, and either constitute a farm unit engaged in the production or growing of agricultural products, or have been farmed by the owner or the owner's parent or spouse for at least 25 years and be used as the residence of the owner and not used for any purpose inconsistent with an agricultural use. Forest land must meet one of two size tests: a single tract of at least 15 acres, or two noncontiguous tracts in the same county totaling at least 15 acres, separated only by a road, a body of water or a public or private easement, that together constitute a forest unit. First-time applications are due March 15, with the county assessor.
Here is the part that lands on buyers. When greenbelt land is converted or disqualified, rollback taxes come due — for agricultural and forest land, the taxes saved for the preceding three years. The manual states that when a sale results in the land being disqualified, the seller is liable "unless otherwise provided by written contract or statute," and that a buyer who declares in writing at the time of sale an intention to continue the greenbelt use, then fails to file an application within 90 days of the sale date, becomes solely responsible. We are not tax advisers — this is why you call the assessor before you sign.
Where does the acreage actually sit, county by county?
One thing first: the acreage is in the unincorporated county around these towns, not inside their limits. Each town below is an orientation point and a set of services; cross the city line and the city's rules replace the county's. Distances are miles from downtown Nashville, as each town's own guide states them.
Davidson and Williamson — where the rural districts run one to five acres. Metro Nashville zones AR2a at two acres and AG at five. Unincorporated Williamson allows a one-acre lot in a traditional subdivision in RP-1 west of I-65 and RD-1 east of it — districts the ordinance intends for low-density residential development "where appropriate infrastructure is available" — and 5 acres in RP-5 and RD-5.
Sumner and Wilson — where the base minimum runs from just under an acre to about two, with Sumner's five-acre trigger. North, unincorporated Sumner County runs Rural Residential at 40,000 square feet and Rural Preservation at 100,000, with the five-acre trigger any time water, hydrant or road falls short. East, unincorporated Wilson County requires 80,000 square feet off public sewer. West, Cheatham County turns rural immediately behind Ashland City — a bottomland bend of the Cumberland about 21 miles out via State Route 12, backed by the 20,000-plus-acre Cheatham Wildlife Management Area — and Pleasant View, a former stagecoach stop on I-24 at Exit 24, about 25 miles northwest. Springfield is the Robertson County seat, an 1879 courthouse on a National Register square with a dark-fired tobacco history, 29 miles north. Portland, the Strawberry Capital of Tennessee, sits at Sumner's north end, and its own city limits cross into Robertson County — so which county you are buying in is an address question there too.
Farther out — Marshall and Maury, where the number comes from the county office. Lewisburg in Marshall County is the founding home of the Tennessee Walking Horse Breeders' & Exhibitors' Association, about 58 miles down the US-31A / I-65 corridor; Mount Pleasant in Maury County — settled in 1824, with a restored downtown square and a phosphate-mining past — about 59 miles out. Neither is a close-in suburb.
This article publishes minimum lot areas only for Sumner, Williamson, Wilson and Davidson. For Cheatham, Robertson, Marshall and Maury, the number comes from that county's own office — all four are linked in step 2 below. Every town here has a guide; the county rung above them exists so far for Sumner County and Williamson County — and the region-wide map of Middle Tennessee towns.
What should you do next?
Work the parcel in this order:
- Confirm the jurisdiction. City or unincorporated county? That decides whose rulebook applies.
- Pull the zoning district and its minimum lot area. Sumner County Planning and Zoning publishes the resolution and map; Williamson County its ordinance and text amendments; the Wilson County Zoning Division holds maps and plats; Metro Nashville posts its classifications. Farther out, the zoning authority is Cheatham County Codes, Building Safety and Land Use, the Robertson County Planning Department, Marshall County Building Codes and Zoning, or Maury County Building and Zoning.
- Pre-screen the soil on USDA Web Soil Survey, then take the septic question to TDEC.
- Check greenbelt status and rollback exposure with the county assessor, using the Comptroller's greenbelt page.
- Estimate the carrying cost with our property tax calculator.
- Look up schools and crime data yourself. Our school and crime data page names eight Middle Tennessee districts, among them Sumner County Schools, Williamson County Schools, Wilson County Schools, Robertson County Schools, Maury County Public Schools and Metro Nashville Public Schools. Cheatham County School District and Marshall County Schools serve the two counties that page does not carry; use the federal NCES district search it links for those. Unincorporated land is generally reported to the FBI's Crime Data Explorer by the county sheriff's office: the Sumner, Williamson, Wilson, Robertson, Cheatham, Marshall and Maury County Sheriff's Offices each report as their own agency, as does the Metropolitan Nashville Police Department. That page also links the Tennessee State Report Card, the NCES school search, district zone lookups and TBI crime statistics. The conclusions are yours.
For the contract-side checklist — perc feasibility, utility extension estimates, recorded road access — see our land and acreage diligence guide. To have someone run these checks with you on a parcel, call the Will Johnson Team at 615-265-1000. We are a Middle Tennessee team at eXp Realty with $27.7 million in volume and 64 transactions as of 2026, and buyer representation comes at little or no cost to you. We will tell you plainly when a parcel's answers are not in the public record yet.
