County outline
Where Lehigh County is located
Area breakdown
Land accounts for 99.2% of Lehigh County’s measured area and water for 0.8%. Its combined area converts to 901.9 square kilometers or approximately 222,856 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 345.336 | 894.416 | 221,015 |
| Water | 2.877 | 7.451 | 1,841.3 |
| Total | 348.213 | 901.868 | 222,856.3 |
How Lehigh County compares
By original Census land area, Lehigh County ranks #62 of 67 in Pennsylvania and #2691 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.529 times the Pennsylvania county-equivalent median of 653.3 square miles. It accounts for 0.8% of the combined county land area in the state.
See the complete Pennsylvania ranking · What counts as a county equivalent?
Population and density of Lehigh County
The Census Bureau estimates that 384,383 people lived in Lehigh County on July 1, 2025. That ranks #201 of 3,222 county equivalents nationally and #10 of 67 in Pennsylvania. Since the April 1, 2020 estimates base of 374,546, the population has grown by 9,837 (+2.6%), compared with +0.4% for Pennsylvania as a whole.
With 345.3 square miles of land, that is 1,113 people per square mile (430 per km²), placing Lehigh County #166 nationally for density and #5 in Pennsylvania. The median county equivalent has 47 people per square mile; the Pennsylvania median is 137. Put another way, there are about 0.575 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 374,449 | 375,852 | 376,746 | 380,068 | 382,939 | 384,383 |
| Change | — | +1,403 | +894 | +3,322 | +2,871 | +1,444 |
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 Lehigh County
Lehigh County is divided into 25 municipalities and townships. In Pennsylvania, county subdivisions are local governments, and together they cover all of the county’s land and residents.
The most populous is Allentown city, with 126,044 residents (32.8% of the county). The largest by land is Lynn township, at 41.3 mi², or 11.9% of the county’s land. Among those with at least 1,000 residents in 2020, Upper Macungie township grew fastest since then (+12.3%).
| County subdivision | Population 2025 | Since 2020 | Land mi² | Share of county land |
|---|---|---|---|---|
| Allentown cityCounty seat | 126,044 | +0.1% | 17.6 | 5.1% |
| Lower Macungie township | 33,507 | +3.3% | 22.4 | 6.5% |
| Upper Macungie township | 29,600 | +12.3% | 26.1 | 7.6% |
| Whitehall township | 29,405 | +0.8% | 12.6 | 3.6% |
| South Whitehall township | 21,655 | +2.8% | 17.1 | 4.9% |
| Bethlehem city | 20,274 | +2.5% | 4.299 | 1.2% |
| Upper Saucon township | 18,217 | +7.3% | 24.5 | 7.1% |
| North Whitehall township | 16,033 | +2.4% | 28.1 | 8.1% |
| Salisbury township | 13,707 | +0.5% | 11.2 | 3.2% |
| Emmaus borough | 12,514 | +7.5% | 2.895 | 0.8% |
| Upper Milford township | 8,254 | +6% | 18 | 5.2% |
| Washington township | 6,647 | +1.8% | 23.6 | 6.8% |
| Catasauqua borough | 6,590 | +1.1% | 1.292 | 0.4% |
| Weisenberg township | 5,102 | +2.5% | 26.8 | 7.8% |
| Fountain Hill borough | 4,835 | +0.1% | 0.735 | 0.2% |
Show the other 10 subdivisions
| Name | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Lynn township | 4,296 | +1.8% | 41.3 |
| Slatington borough | 4,296 | +0.3% | 1.322 |
| Lower Milford township | 3,898 | +0.9% | 19.7 |
| Coplay borough | 3,532 | +5.6% | 0.61 |
| Heidelberg township | 3,411 | +1.9% | 24.7 |
| Macungie borough | 3,395 | +4.3% | 0.989 |
| Alburtis borough | 2,609 | +0.8% | 0.707 |
| Coopersburg borough | 2,535 | +4% | 0.933 |
| Lowhill township | 2,331 | +2.6% | 14 |
| Hanover township | 1,696 | +0.3% | 4.221 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Lehigh County. Land: 2026 Census Gazetteer. How communities are listed.
Metropolitan area
Lehigh County is a central county of the Allentown-Bethlehem-Easton, PA-NJ Metropolitan Statistical Area. Its 4 county equivalents have 887,615 residents on 1,453 square miles of land; Lehigh County accounts for 23.8% of the land and 43.3% of the residents. By combined land it ranks #227 of 393 metropolitan areas, and #70 by population. It belongs to the Allentown-Bethlehem-East Stroudsburg, PA-NJ Combined Statistical Area.
| County equivalent | Population 2025 | Land mi² |
|---|---|---|
| Lehigh County | 384,383 | 345.3 |
| Northampton County | 324,411 | 369.8 |
| Warren CountyNew Jersey | 112,953 | 356.5 |
| Carbon County | 65,868 | 381.4 |
ZIP codes
36 ZIP Code Tabulation Areas have land in Lehigh County; 28 of them have most of their land inside the county, and the others mainly cover neighboring areas.
180111801518017180181803118032180341803618037180411804618049180511805218053180591806218065180661806918078180791808018087180921810118102181031810418106181091819518951195291953019539
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 Lehigh County
Lehigh County shares a land border with 6 county equivalents. Each of them has more land than Lehigh County. The largest neighbor is Berks County (856.4 mi²) and the smallest is Northampton County (369.8 mi²). Together with its neighbors, Lehigh County forms a block of 3,819 mi² of land, of which it holds 9%.
| Bordering county equivalent | Land mi² | Size vs. Lehigh | Compare |
|---|---|---|---|
| Berks County | 856.4 | 2.5× larger | Compare |
| Schuylkill County | 778.8 | 2.3× larger | Compare |
| Bucks County | 604.4 | 1.8× larger | Compare |
| Montgomery County | 482.9 | 1.4× larger | Compare |
| Carbon County | 381.4 | 1.1× larger | Compare |
| Northampton County | 369.8 | 1.1× larger | Compare |
How big is Lehigh County compared with U.S. states?
Lehigh County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 3 times as much. Pennsylvania’s county land could hold about 130 areas the size of Lehigh County.
Another way to picture it: the same land area would fill a square about 18.6 miles (29.9 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 Lehigh County?
Lehigh County has more land than 531 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 Lehigh County at #2,735 nationally by total area, 44 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 0.8%, compared with a national county-equivalent median of 1.2% — 0.3 percentage points lower. 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 Lehigh County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #2690 | Putnam County, West Virginia | 345.7 | Compare |
| #2691 | Lehigh County, Pennsylvania | 345.3 | This county |
| #2692 | Jackson County, Kentucky | 345.2 | 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 40.614241, -75.590627. 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: 894,414,847 m²; AWATER: 7,450,566 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 Lehigh County?
Lehigh County, Pennsylvania has 345.3 square miles (894.4 km²) of land and 2.877 square miles of water, for a total area of 348.2 square miles. It ranks #2691 of 3,222 U.S. county equivalents by land area.
Is Lehigh County the largest county in Pennsylvania?
No. Lehigh County ranks #62 of 67 in Pennsylvania by land area. The largest is Lycoming County, with 1,228.9 square miles of land.
What counties border Lehigh County?
Lehigh County shares a land border with Berks County, Northampton County, Bucks County, Carbon County, Schuylkill County, and Montgomery County.
What is the population of Lehigh County?
The Census Bureau estimates Lehigh County had 384,383 residents on July 1, 2025, ranking #201 of 3,222 county equivalents. That is 1,113 people per square mile of land.
What is the county seat of Lehigh County?
The county seat of Lehigh County is Allentown.
What cities and towns are in Lehigh County?
Lehigh County has 25 county subdivisions (cities, towns and townships). The most populous five are Allentown city, Lower Macungie township, Upper Macungie township, Whitehall township, and South Whitehall township.
Is Lehigh County part of a metropolitan area?
Yes. It is a central county of the Allentown-Bethlehem-Easton, PA-NJ Metropolitan Statistical Area, which has 4 county equivalents and 887,615 residents.
How many ZIP codes are in Lehigh County?
36 ZIP Code Tabulation Areas have land in Lehigh County, and 28 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Lehigh County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 3 times as much land.
How many acres of land are in Lehigh County?
The land measurement converts to approximately 221,015 acres. Including water, total area is approximately 222,856 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.