Howard County, Maryland

Howard County is a county in Maryland, United States, about 15 miles west of Baltimore and 25 miles northeast of Washington, DC. It had a population of 332,317 at the 2020 census, an estimated 339,183 by 2025, and covers 253 square miles in total, 251 of them land (650 km2), centred near 39°15′N 76°56′W.

Ellicott City is the county seat; its postal code is 21043. Howard County has no incorporated cities or towns at all — every community, including the seat, is unincorporated and governed directly by the county. It runs on Eastern Time, and its FIPS code is 24027.

Towns & Villages in Howard County

Howard County has 22 principal communities on record: 11 census designated places and 11 smaller unincorporated settlements. CDP stands for census designated place, a boundary the Census Bureau draws purely for counting; Unincorp. covers crossroads and rural communities with no formal boundary or count of their own. None of them is a municipality.

Three entries need a caveat. Jessup’s 10,535 residents are split between Howard and Anne Arundel counties — the CDP straddles the line at the Baltimore-Washington Parkway. North Laurel is often written simply as “Laurel” in mailing addresses, but the incorporated City of Laurel itself sits across the Patuxent River in Prince George’s County. And Daniels is a former mill village on the Patapsco, largely abandoned after Hurricane Agnes flooded it in 1972; its remains now sit inside Patapsco Valley State Park.

ZIP Codes

• 21042 — Ellicott City (western half)
• 21043 — Ellicott City (also serves 21041, an Ellicott City PO box ZIP)
• 21044, 21045, 21046 — Columbia (west, east and south respectively)
• 21075 — Elkridge
• 20723 — Laurel (covers North Laurel and much of Scaggsville)
• 20794 — Jessup
• 20759 — Fulton
• 20763 — Savage
• 20777 — Highland
• 21029 — Clarksville
• 21036 — Dayton
• 21723 — Cooksville
• 21737 — Glenelg
• 21738 — Glenwood
• 21794 — West Friendship
• 21797 — Woodbine
• 21163 — Woodstock
• 20701 — Annapolis Junction
• 21076 — Hanover (shared with Anne Arundel County)
• 21150 — Simpsonville (PO box only)
• 21765 — Lisbon (PO box only)

Ilchester and Daniels have no ZIP code of their own; their mail is delivered under the neighbouring Ellicott City and Elkridge codes. Scaggsville addresses run under Laurel’s 20723 and Fulton’s 20759.

Geography

Howard County sits on Maryland’s Piedmont plateau, rolling upland that slopes from about 800 feet in the west down toward the fall line at Elkridge. Of its 253 square miles, 251 are land and about 2.7 are water — roughly one percent. The Patapsco River forms the entire northern and northeastern border, most of it inside Patapsco Valley State Park, and the Patuxent River forms the southwestern border, impounded there as the Triadelphia and Rocky Gorge reservoirs, which supply drinking water to the Washington suburbs.

Carroll County lies to the north and Baltimore County to the northeast, both across the Patapsco. Frederick County touches the county’s western tip, Montgomery County and Prince George’s County lie across the Patuxent to the southwest and south, and Anne Arundel County borders it on the southeast. Montgomery County is the only neighbour that shares both a river border and the county’s commuter orbit toward Washington.

Demographics

Howard County counted 332,317 people in 2020, and the Census Bureau’s estimate had reached 339,183 by 2025. Columbia, with 104,681 residents, and Ellicott City, with 75,947, together hold more than half the county’s population. Density works out to about 1,324 people per square mile of land, though that average hides a sharp split: the eastern corridor from Elkridge to North Laurel is fully suburban, while the west around Glenelg, Glenwood and Lisbon stays horse-farm rural. Median household income was $149,763 in 2024, well above Maryland’s statewide $103,678, and the county routinely places among the wealthiest in the United States.

Economy & Local Life

Professional, scientific and technical services employ the most county residents, about 32,878 people, followed by health care and social assistance at 23,911 and educational services at 21,132. The Johns Hopkins University Applied Physics Laboratory, near North Laurel, is the largest single employer with roughly 8,000 staff building spacecraft and defense systems. Columbia’s town centre holds The Mall in Columbia and the Merriweather Post Pavilion amphitheatre, and the Howard County General Hospital campus anchors health care employment. The county school system regularly ranks first in Maryland, a fact that drives much of its housing demand. The biggest annual event is the Howard County Fair, held each August at the fairgrounds in West Friendship.

History

The area was settled in the early 1700s as tobacco country within Anne Arundel County. The Ellicott brothers, Quaker millers from Pennsylvania, founded Ellicott’s Mills on the Patapsco in 1772 and turned the district toward wheat; in 1830 the Baltimore and Ohio Railroad made the town its first terminus, the earliest railroad destination in the United States. Maryland set the area apart as the Howard District of Anne Arundel County in 1838, then made it a full county under the constitution of 1851. It is named for John Eager Howard, Revolutionary War colonel and fifth governor of Maryland.

Two modern events define the county. In 1967 developer James Rouse opened Columbia, one of America’s most ambitious planned communities, built on 14,000 quietly assembled acres and organised into ten self-contained villages; it is now Maryland’s second-largest community. And in July 2016 and again in May 2018, catastrophic flash floods tore down Ellicott City’s historic Main Street, killing three people in total and forcing a continuing programme of flood tunnels and building removals along the Tiber branch.

Getting There

Interstate 70 crosses the county’s northern half from Woodbine past West Friendship to Ellicott City, and Interstate 95 cuts the southeastern corridor between Elkridge and North Laurel. US 29 links the two through Columbia, US 1 and US 40 carry the old Baltimore roads, and MD 32, MD 100 and MD 108 complete the grid.

• Baltimore — about 15 miles northeast
• Washington, DC — about 25 miles southwest
• Annapolis — about 30 miles southeast
• Frederick — about 35 miles west

Baltimore/Washington International Thurgood Marshall Airport sits just across the Anne Arundel line, roughly 10 minutes from Elkridge. MARC’s Camden Line commuter trains stop at Savage on the Baltimore–Washington run, and the nearest Amtrak station is BWI Rail Station at the airport.

Frequently Asked Questions

Where is Howard County located?
In central Maryland between Baltimore and Washington, DC, bounded by the Patapsco River on the north and the Patuxent River on the southwest.

What is the population of Howard County?
332,317 at the 2020 census, with a 2025 estimate of 339,183.

How big is Howard County?
253 square miles in total, of which 251 square miles are land and about 2.7 square miles are water.

What is the county seat of Howard County?
Ellicott City — one of the largest unincorporated county seats in the United States, since Howard County has no incorporated municipalities.

How many towns and cities are in Howard County?
None are incorporated. The county has 11 census designated places — led by Columbia, Ellicott City, Ilchester, North Laurel and Elkridge — plus about a dozen unincorporated villages such as Clarksville, Glenelg and Woodbine.

What ZIP codes does Howard County use?
21042 and 21043 for Ellicott City; 21044, 21045 and 21046 for Columbia; 21075 for Elkridge; 20723 for North Laurel; plus 15 more covering the smaller communities, from 20701 to 21797.

What is Howard County known for?
Columbia, James Rouse’s 1967 planned community; historic Ellicott City, the B&O Railroad’s first terminus in 1830; and one of the highest median household incomes of any US county.

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