Farmland in Montgomery County, MD: The Ag Reserve & TDRs

Established in 1980 and covering roughly a third of the county, Montgomery's Agricultural Reserve is one of the country's most studied farmland preservation programs -- not because it bans development outright, but because it built a market in development rights that lets a farm owner sell what the zoning takes away. Here's what that means if you're buying land inside the Reserve boundary.

This page covers what's specific to Montgomery County. For the general explanation, see the national guide.

Why the Reserve exists: downzoning paired with a market, not a ban

By the late 1970s, Montgomery County's rural north and west faced the same fate that has since overtaken farmland in many DC-adjacent counties: a 5-acre-minimum Rural Zone that, left in place, would eventually have chopped the area into large-lot suburban estates rather than preserved working farms. In 1980, the County Council took a different approach, designating roughly 93,000 acres -- close to a third of the county's total land -- as a permanent Agricultural Reserve, and rezoning most of it into a new Rural Density Transfer (RDT) category that cut by-right density to just one house per 25 acres.

What makes Montgomery's program distinctive nationally isn't the downzoning alone -- plenty of jurisdictions have done that -- it's what came with it: every RDT-zoned property was granted transferable development rights (TDRs) at a rate of one TDR per 5 acres, reflecting the density the land gave up. A farm owner who agrees to forgo development beyond the 25-acre floor can sell those TDRs to developers building in the county's designated growth corridors, capturing real cash value for development rights without having to build on the farm itself or sell the land outright. That market-based structure is why the Reserve has survived, largely intact, for more than four decades.

What "47,903 acres preserved" actually means -- and what it doesn't

A 2023 report from the county's own Office of Legislative Oversight put the total acreage preserved specifically through the TDR mechanism at 47,903 acres as of 2022. That's a substantial number, but it is roughly half of the Reserve's approximately 93,000-acre total footprint, not the whole thing -- meaning a meaningful share of Reserve land still holds its original, unsold TDRs. For a buyer, this is the single most important thing to verify on any specific Reserve parcel: has this property's TDRs already been sold?

If a farm's TDRs have already been sold, that restriction runs with the land, similar in effect to a conservation easement -- it binds you as a future owner regardless of what a listing implies about the property's development potential, and it typically cannot be undone by a later owner. If the TDRs are still attached to the property, you as the buyer would be acquiring both the land and that unsold development-rights asset, which carries its own market value separate from the land's value for farming, a homesite, or recreational use -- and which you could, in principle, choose to sell yourself later, subject to the county's current TDR market conditions and receiving-area demand.

What to check before buying land in the Agricultural Reserve

Three concrete steps: (1) confirm with the Montgomery County Planning Department (part of the bi-county Maryland-National Capital Park and Planning Commission) exactly which zone applies to the parcel -- RDT is the primary Reserve zone, but not the only one, and the specific zone determines both by-right density and TDR eligibility; (2) ask the Planning Department or do a title search to determine whether the parcel's TDRs have already been sold, since an unsold-TDR property carries meaningfully different value and future flexibility than one where the rights are gone; and (3) if you're buying specifically for TDR value rather than to farm or build a single home, confirm current TDR market pricing and whether the county's designated receiving areas are still actively accepting transfers, since TDR markets can soften or tighten over time based on how much growth-area development is actually happening.

It's also worth knowing what the Reserve does not do: it does not prohibit agricultural use, does not prevent a sale of the land, and does not require the owner to actively farm it (though many Reserve landowners do, and the county's Office of Agriculture supports a genuinely active farm economy inside the boundary, from row crops and livestock to horse farms, wineries, and agritourism operations). A Reserve property can be a working farm, a large residential homestead at 25-acre density, or an unbuilt parcel still holding sellable TDRs -- confirm which situation you're actually looking at before assuming either the most restrictive or the most permissive interpretation.

Farmland in the Montgomery County Agricultural Reserve: TDRs and What They Mean for Buyers

Why the Reserve exists: downzoning paired with a market, not a ban

What "47,903 acres preserved" actually means -- and what it doesn't

What to check before buying land in the Agricultural Reserve

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