Glen Cove Avenue is a major, 3.45-mile (5.55 km) road connecting Roslyn Harbor and Glen Cove in Nassau County, on Long Island, New York, in the United States.

[2][3][4][5] It then continues north through Roslyn Harbor, passing Back Road and eventually entering Glenwood Landing, still continuing north and eventually reaching University Place.

[2][3][4][5] CR C91 then continues heading towards the north, intersecting with Craft Avenue, Shore Road (CR E25), and then Morris Avenue in Glen Cove before reaching Pratt Boulevard.

[7][8] Among the project's opponents were several members of the Oyster Bay Town Council, who claimed that the widening would lead to downzoning and urbanization, echoing the concerns expressed by many of the residents in the vicinity of the road.

[9] It, along with all of the other county routes in Nassau County, became unsigned in the 1970s, when Nassau County officials opted to remove the signs as opposed to allocating the funds for replacing them with new ones that met the latest federal design standards and requirements, as per the federal government's Manual on Uniform Traffic Control Devices.