EXHIBIT 21.1 CORPORATE OFFICE PROPERTIES TRUST SUBSIDIARIES OF REGISTRANT DELAWARE Airport Square Holdings I, LLC Airport Square Holdings VI and VII, LLC Blue Bell Investment Company, LP Comcourt Investors, LP COPT Acquisitions, Inc. COPT Concourse, LLC Corporate Office Properties, LP Corporate Office Properties Holdings, Inc. Delaware Airport III, LLC Delaware Airport VIII, LLC Delaware Airport IX, LLC South Brunswick Investors, LP MARYLAND Airport Square, LLC Airport Square II, LLC Airport Square IV, LLC Airport Square V, LLC Airport Square X, LLC Airport Square XI, LLC Airport Square XIII, LLC Airport Square XIV, LLC Airport Square XV, LLC Airport Square XIX, LLC Airport Square XX, LLC Airport Square XXI, LLC Airport Square XXII, LLC Airport Square Storms, LLC Atrium Building, LLC Brown's Wharf, LLC Commons Office Research, LLC Concourse 1304, LLC COPT Columbia, LLC COPT Gate 63, LLC COPT Gate 6700-6708-6724, LLC COPT Gateway, LLC COR, LLC Corporate Development Services, LLC Corporate Gatespring, LLC Corporate Gatespring II, LLC Corporate Management Services, LLC Corporate Office Management, Inc. Corporate Office Services, LLC Corporate Paragon, LLC Corporate Property, LLC Corporate Realty Management, LLC Corporate Realty Advisors, LLC Cornucopia Holdings, LLC Cornucopia Holdings II, LLC Gateway 44, LLC Gateway 63, LLC Honeyland 108, LLC Lakeview at the Greens, LLC Martin G. Knott & Associates, LLC NBP One, LLC NBP Huff & Puff, LLC NBP Retail, LLC NBP 131-133-141, LLC NBP 132, LLC NBP 134, LLC NBP 135, LLC NBP 201, LLC NBP 201 Holdings, LLC NBP 211, LLC NBP 211 Holdings, LLC NBP 220, LLC NBP 221, LLC St. Barnabas, LLC Tech Park I, LLC Tech Park II, LLC Tech Park IV, LLC Three Centre Park, LLC 9690 Deereco Road, LLC 7318 Parkway Drive Enterprises, LLC 7321 Parkway Drive Enterprises, LLC 7240 Parkway Drive Enterprises, LLC 7200 Riverwood, LLC 6711 Gateway, LLC 6731 Gateway, LLC NEW JERSEY Cuaba Associates, LLC Princeton Executive, LLC 68 Culver, LLC PENNSYLVANIA Bolivar Associates, LLC Corporate Gateway General Partnership COPT Gateway, LP Gateway Central Limited Partnership 6385 Flank Drive, LP VIRGINIA COPT Chantilly, LLC