Carroll County, Maryland

Carroll County is a county in Maryland, United States, about 30 miles northwest of Baltimore. It
had a population of 172,891 at the 2020 census, an estimated 176,677 by 2025, and covers 453
square miles (1,170 km2), of which 448 are land, centred near 39°34′N 77°01′W.

Westminster is the county seat; its postal code is 21157. The county holds 2 cities, 6
incorporated towns and dozens of unincorporated communities, and it runs on Eastern Time. Its
FIPS code is 24013.

Towns & Villages in Carroll County

Carroll County has 9 incorporated or census-recognized places with 2020 population counts, plus
more than two dozen unincorporated crossroads communities with no local government of their own.
CDP stands for census designated place; Unincorp. covers hamlets and rural crossroads with no
formal boundary.

Beyond that list, Wikipedia names another eighteen unincorporated crossroads in the county
— Alesia, Carrollton, Carrolltowne, Frizzelburg, Gaither, Greenmount, Harney, Henryton,
Jasontown, Lineboro, Linwood, Mayberry, Middleburg, Millers, Patapsco, Pleasant Valley, Uniontown
and Woodstock among them — with no population or ZIP data of their own; mail there routes
through a nearby incorporated town’s code instead. Three places straddle county lines: Mount
Airy sits mostly in Carroll but extends into Frederick County, Sykesville sits mostly in Carroll
but crosses into Howard County, and Marriottsville is split three ways between Carroll, Howard and
Baltimore counties.

ZIP Codes

• 21157 — Westminster (also serves 21158, a Westminster PO box ZIP)
• 21784 — Eldersburg and Sykesville
• 21771 — Mount Airy
• 21787 — Taneytown
• 21074 — Hampstead
• 21102 — Manchester (also 21088)
• 21776 — New Windsor
• 21791 — Union Bridge
• 21048 — Finksburg
• 21104 — Marriottsville
• 21797 — Woodbine

Gamber, Detour, Keymar, Silver Run, Uniontown, Union Mills and the smaller crossroads named
above have no ZIP code of their own; the U.S. Postal Service delivers mail there under a
neighboring incorporated town’s code, mostly Westminster’s 21157 or 21158.

Geography

Carroll County sits in Maryland’s Piedmont Plateau, a belt of rolling hills between the
Blue Ridge and the Chesapeake Bay lowlands. Of its 453 total square miles, 448 are land and 5.1
are water, about 1.1 percent — the county has no large natural lake, and its main surface
water is the Patapsco River, which forms part of its southern boundary with Howard County, and
Liberty Reservoir, which supplies drinking water to Baltimore and sits partly within the
county’s southeastern corner.

York County and Adams County, both in Pennsylvania, border Carroll to the north. Baltimore
County lies to the east, Howard County to the south, Montgomery County touches the southwest
corner, and Frederick County lies to the west. York County, Adams County, Baltimore County, Howard County and Montgomery County all have
their own pages on this site; Frederick County, Maryland does not yet have one.

Demographics

Carroll County had a population of 172,891 at the 2020 census, and the latest estimate puts the
county near 176,677 residents. Eldersburg and Westminster are by far the two largest communities,
together holding roughly a third of the county’s population. Population density works out to
about 386 people per square mile of land, moderate for a Baltimore-area suburban county and far
below neighboring Baltimore and Howard counties. Maryland’s statewide median household
income was $98,678 (2023 ACS), the highest of any U.S. state; Carroll ranks among Maryland’s
higher-income suburban counties, though its own current median has not been independently
verified for this page.

Economy & Local Life

Carroll County Public Schools is the county’s largest employer, with 3,334 workers across
its district, the ninth-largest in Maryland. Carroll Hospital Center in Westminster is another
major employer, along with McDaniel College, a private liberal-arts college also in Westminster,
and a large Penguin Random House book-distribution center. JoS. A. Bank Clothiers, the menswear
retailer, has its corporate roots in the county. Farming remains a visible part of county life away
from the Eldersburg and Mount Airy suburbs, with dairy and grain operations concentrated in the
county’s northern and western townships. The Maryland Wine Festival has been held each autumn
at the Carroll County Farm Museum in Westminster since 1985, drawing visitors from across the
Baltimore-Washington area.

History

Maryland’s General Assembly formed Carroll County on 19 January 1837, carving it out of
Baltimore and Frederick counties. It was named for Charles Carroll of Carrollton, the last
surviving signer of the Declaration of Independence, who died in 1832. Westminster was designated
the county seat.

On 29 June 1863, Union cavalry troopers clashed with J.E.B. Stuart’s Confederate cavalry
on Westminster’s Main Street in an engagement now known as Corbit’s Charge. The
skirmish delayed Stuart’s column by several hours as it rode north toward Pennsylvania,
a delay some historians credit with keeping Stuart’s cavalry away from the opening day of
the Battle of Gettysburg two days later.

Getting There

Interstate 70, running with US Route 40, clips the county’s southern edge near Mount Airy.
Maryland Route 140 is the main east–west corridor through Westminster, and MD 26, MD 27, MD
30, MD 31, MD 32 and MD 97 carry most of the county’s other through traffic. No passenger
rail line or intercity bus route serves the county; local opposition has kept it off the regional
transit map for decades.

• Baltimore — about 30 miles southeast
• Frederick — about 25 miles southwest
• Gettysburg, Pennsylvania — about 25 miles north
• Washington, D.C. — about 50 miles south

Baltimore/Washington International Thurgood Marshall Airport (BWI), roughly 30 miles southeast
of Westminster, is the nearest major commercial airport. The nearest Amtrak service is the BWI
Rail Station, which also carries MARC commuter trains toward Baltimore and Washington.

Frequently Asked Questions

Where is Carroll County located?
It sits in Maryland’s Piedmont Plateau, about 30 miles northwest of Baltimore, bordered by
York and Adams counties in Pennsylvania and by Baltimore, Howard, Montgomery and Frederick
counties in Maryland.

What is the population of Carroll County?
172,891 at the 2020 census, with a 2025 estimate near 176,677.

How big is Carroll County?
453 square miles total (1,170 km2), of which 448 square miles are land.

What is the county seat of Carroll County?
Westminster, formed with the county in 1837, is the county seat.

How many towns and cities are in Carroll County?
Two cities — Westminster and Taneytown — six incorporated towns (Mount Airy,
Hampstead, Manchester, Sykesville, New Windsor and Union Bridge), and the unincorporated Eldersburg
CDP, the county’s largest community, plus more than two dozen smaller crossroads.

What ZIP codes does Carroll County use?
21157 and 21158 for Westminster; 21784 for Eldersburg and Sykesville; 21771 for Mount Airy; 21787
for Taneytown; 21074 for Hampstead; 21102 for Manchester; 21776 for New Windsor; and 21791 for
Union Bridge.

What is Carroll County known for?
Corbit’s Charge, the 1863 cavalry skirmish in Westminster that delayed J.E.B. Stuart ahead of
Gettysburg, and the annual Maryland Wine Festival at the Carroll County Farm Museum.

More counties in this state: Towns and villages in Maryland.