|Country||United States of America|
|• Total||10.8 sq mi (28.0 km2)|
|• Land||10.7 sq mi (27.8 km2)|
|• Water||0.08 sq mi (0.2 km2)|
|Elevation||100 ft (30 m)|
|• Density||2,200/sq mi (840/km2)|
|Time zone||Eastern (EST) (UTC-5)|
|• Summer (DST)||EDT (UTC-4)|
|GNIS feature ID||588678|
Ilchester is an unincorporated community and census-designated place in Howard County, Maryland, United States. The population was 23,476 at the 2010 census. It was named after the village of Ilchester in the English county of Somerset.
Originally located about 2 miles (3 km) southeast of Ellicott City along the Patapsco River, Ilchester was settled by the Ellicott family (John, Andrew, and Joseph Ellicott) in the late 18th century. The Baltimore and Ohio Railroad (B&O) was built up the Patapsco River valley through Ilchester in 1830 (see Old Main Line Subdivision), and George Ellicott, Jr. (grandson of Andrew) built a tavern along the railroad. Ilchester did not become a major stop for the B&O, and the tavern was unsuccessful. Ellicott sold the tavern to a Redemptorist church order in 1866.
The church used the Ellicott estate to start a college, initially called Mount Saint Clemens when it opened in 1868. Several additions to the original building were made, and a chapel was constructed. In 1882 it was renamed Saint Mary's College. In 1893 the chapel was established as a parish church dedicated to "Our Lady of Perpetual Help". The parish moved the church to a nearby facility in the 1950s. Enrollment at the college declined, and the college was closed in 1972. The State of Maryland purchased a portion of the campus in 1987 and added the land to adjacent Patapsco Valley State Park.
Ilchester is located at  It is situated in Howard County, Maryland, between Ellicott City to the northwest and Elkridge to the southeast. Columbia is to the southwest. The Patapsco River forms the northeast boundary of the community and serves as the county line, with Baltimore County and the community of Catonsville across the river.(39.2509, -76.7647).
The original mill community of Ilchester is located along the Patapsco River at the junction of Ilchester Road and Bonnie Branch Road. However, the current CDP extends southwest to include the suburban terrain of Howard County outside of the Patapsco River valley. Maryland Route 103, Montgomery Road, is the main local road through the CDP. Maryland Route 100 is a freeway that runs through the southern part of Ilchester, serving the community at Exit 4 with Montgomery Road. To the south, Route 100 intersects with Interstate 95, which forms the southeastern boundary of the Ilchester CDP.
According to the United States Census Bureau, the CDP has a total area of 10.8 square miles (28.0 km2), of which 10.7 square miles (27.8 km2) is land and 0.08 square miles (0.2 km2), or 0.57%, is water.
In popular culture
The season four finale of the television show Supernatural took place at a fictional church in Ilchester.
- Ilchester Tunnel (B&O Railroad)
- "Profile of General Population and Housing Characteristics: 2010 Demographic Profile Data (DP-1): Ilchester CDP, Maryland". U.S. Census Bureau, American Factfinder. Retrieved February 22, 2012.
- Michael Duck, "The Story Beneath The Ruins: A History of St. Mary's College in Ilchester", The View from Ellicott City (newspaper). October 19, 2000.
- "US Gazetteer files: 2010, 2000, and 1990". United States Census Bureau. 2011-02-12. Retrieved 2011-04-23.
- "Geographic Identifiers: 2010 Demographic Profile Data (G001): Ilchester CDP, Maryland". U.S. Census Bureau, American Factfinder. Retrieved February 22, 2012.