Timonium /ˌtɪˈmoʊniːəm/ is a census-designated place (CDP) in Baltimore County, Maryland, United States.

The original Timonium was an incomplete palace Mark Antony built on the island of Antirhodos in the harbor of Alexandria, Egypt.

[4] According to the United States Census Bureau, the CDP has a total area of 5.4 square miles (13.9 km2), all land.

It is bordered on the north by Cockeysville, on the south by Lutherville, on the east by Loch Raven Reservoir, and on the west by Falls Road (Maryland Route 25), with the Greenspring and Worthington Valleys beyond.

In addition, bus routes 8 and 9 provide regular service along the York Road corridor.