County Route 21 (Suffolk County, New York)

Former standard route marker for county routes in Suffolk County; CR 13A shield on CR 50 in Bay Shore.
Highway names
Interstates:	Interstate X (I-X)
US Highways:	U.S. Route X (US X)
State:	New York State Route X (NY X)
County:	County Route X (CR X)
System links
New York Highways Interstate U.S. State Reference Parkways

County routes in Suffolk County, New York, are maintained by the Suffolk County Department of Public Works and signed with the Manual on Uniform Traffic Control Devices-standard yellow-on-blue pentagon route marker. The designations do not follow any fixed pattern. Routes 1 to 25 are listed below.

County Route 1 is known as County Line Road and extends for 1.54 miles (2.48 km) through the town of Babylon. It begins at NY 27A (Montauk Highway) in Amityville and heads north to the intersection of Joyce Avenue in East Farmingdale. Parts of the road enter Nassau County; however, the Nassau County sections are not part of CR 1.

County Route 2 is mostly known as Straight Path and extends from the village of Amityville to the town of Huntington. It begins at an intersection with NY 110 in Amityville and heads east along Dixon Avenue to CR 47 in Copiague. From there it begins to move to the northeast until it eventually becomes Straight Path before the intersection with NY 27 in North Lindenhurst. The road widens into a four-lane divided highway ahead of its junction with CR 3 (Wellwood Avenue). This intersection contains turning ramps on all corners except the southwest corner, where Heathcoat Road ends. The divider ends at Sherebrook Road and the North Lindenhurst Fire Department, where the road returns to a four-lane undivided highway.