County outline
Where Lamar County is located
Area breakdown
Land accounts for 98.7% of Lamar County’s measured area and water for 1.3%. Its combined area converts to 481.3 square kilometers or approximately 118,934 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 183.501 | 475.265 | 117,440.6 |
| Water | 2.334 | 6.045 | 1,493.8 |
| Total | 185.835 | 481.31 | 118,934.4 |
How Lamar County compares
By original Census land area, Lamar County ranks #146 of 159 in Georgia and #3025 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.535 times the Georgia county-equivalent median of 342.7 square miles. It accounts for 0.3% of the combined county land area in the state.
See the complete Georgia ranking · What counts as a county equivalent?
Population and density of Lamar County
The Census Bureau estimates that 20,941 people lived in Lamar County on July 1, 2025. That ranks #1,834 of 3,222 county equivalents nationally and #89 of 159 in Georgia. Since the April 1, 2020 estimates base of 18,505, the population has grown by 2,436 (+13.2%), compared with +5.5% for Georgia as a whole.
With 183.5 square miles of land, that is 114 people per square mile (44 per km²), placing Lamar County #910 nationally for density and #58 in Georgia. The median county equivalent has 47 people per square mile; the Georgia median is 69. Put another way, there are about 5.6 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 18,555 | 18,700 | 19,465 | 20,377 | 20,639 | 20,941 |
| Change | — | +145 | +765 | +912 | +262 | +302 |
U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.
Cities and towns in Lamar County
3 incorporated places lie at least partly in Lamar County. Together they are home to 7,340 people (35.1%); the other 13,601 (64.9%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is Barnesville city, with 6,329 residents in the county.
| Incorporated place | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Barnesville cityCounty seat | 6,329 | +3.4% | 6.06 |
| Milner city | 819 | +6.5% | 2.108 |
| Aldora town | 192 | +16.4% | 0.253 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Lamar County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.
Metropolitan area
Lamar County is not part of any metropolitan or micropolitan statistical area in the Office of Management and Budget’s July 2023 delineation; 1,306 other county equivalents are also outside one. These areas are built around an urban core of at least 10,000 people plus the counties tied to it by commuting, so counties outside them are generally rural.
ZIP codes
9 ZIP Code Tabulation Areas have land in Lamar County; 2 of them have most of their land inside the county, and the others mainly cover neighboring areas.
302043022430233302563025730285302953101631097
ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.
Counties bordering Lamar County
Lamar County shares a land border with 5 county equivalents. Each of them has more land than Lamar County. The largest neighbor is Monroe County (396.1 mi²) and the smallest is Butts County (183.7 mi²). Together with its neighbors, Lamar County forms a block of 1,498.8 mi² of land, of which it holds 12.2%.
| Bordering county equivalent | Land mi² | Size vs. Lamar | Compare |
|---|---|---|---|
| Monroe County | 396.1 | 2.2× larger | Compare |
| Upson County | 323.5 | 1.8× larger | Compare |
| Pike County | 216.1 | 1.2× larger | Compare |
| Spalding County | 196 | 1.1× larger | Compare |
| Butts County | 183.7 | about the same | Compare |
How big is Lamar County compared with U.S. states?
Lamar County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 5.6 times as much. Georgia’s county land could hold about 315 areas the size of Lamar County.
Another way to picture it: the same land area would fill a square about 13.5 miles (21.8 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.
State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.
What stands out about Lamar County?
Lamar County has more land than 197 of the other 3,221 county equivalents in the dataset.
A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.
Does including water change its rank?
Using land plus water places Lamar County at #3,047 nationally by total area, 22 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.
Its water share is 1.3%, compared with a national county-equivalent median of 1.2%. The two percentages are within 0.1 percentage points of each other. This describes the statistical geography’s land/water mix, not flood exposure or developable land.
Closest positions in the national land ranking
These entries sit immediately beside Lamar County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #3024 | Butts County, Georgia | 183.7 | Compare |
| #3025 | Lamar County, Georgia | 183.5 | This county |
| #3026 | Charles City County, Virginia | 182.9 | Compare |
Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.
Representative coordinates
The Census internal point is 33.074440, -84.146689. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.
Source and precision
U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 475,264,410 m²; AWATER: 6,044,329 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.
Common questions
How big is Lamar County?
Lamar County, Georgia has 183.5 square miles (475.3 km²) of land and 2.334 square miles of water, for a total area of 185.8 square miles. It ranks #3025 of 3,222 U.S. county equivalents by land area.
Is Lamar County the largest county in Georgia?
No. Lamar County ranks #146 of 159 in Georgia by land area. The largest is Ware County, with 899.4 square miles of land.
What counties border Lamar County?
Lamar County shares a land border with Monroe County, Pike County, Upson County, Spalding County, and Butts County.
What is the population of Lamar County?
The Census Bureau estimates Lamar County had 20,941 residents on July 1, 2025, ranking #1,834 of 3,222 county equivalents. That is 114 people per square mile of land.
What is the county seat of Lamar County?
The county seat of Lamar County is Barnesville.
What cities and towns are in Lamar County?
Lamar County has 3 incorporated places. The most populous are Barnesville city, Milner city, and Aldora town; 13,601 residents live outside any incorporated place.
Is Lamar County part of a metropolitan area?
No. Lamar County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.
How many ZIP codes are in Lamar County?
9 ZIP Code Tabulation Areas have land in Lamar County, and 2 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Lamar County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 5.6 times as much land.
How many acres of land are in Lamar County?
The land measurement converts to approximately 117,441 acres. Including water, total area is approximately 118,934 acres. One square mile equals 640 acres.
Why might another source show a different area?
Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.
Can this establish a property boundary?
No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.