New York State Route 3A is an east–west state highway in Jefferson County, New York, United States, that was established in the 1950s.

New York State Route 3A may also refer to:

• New York State Route 3A (1930–1932) in eastern Niagara and Orleans Counties
• New York State Route 3A (1932–1935) in central Niagara County

• Maryland Route 251
• Maryland Route 251 (1930s)
• Maryland Route 252
• Maryland Route 254 (1930s)
• Maryland Route 254 (former)
• Maryland Route 266
• Maryland Route 268 (1930s)
• Maryland Route 268 (former)
• Maryland Route 27 (1920s-1930s)
• Maryland Route 27 (former)
• Maryland Route 293
• Maryland Route 294
• Maryland Route 295 (former)
• Maryland Route 296
• Maryland Route 29 (former)
• Maryland Route 303 (1930s-1950s)
• Maryland Route 315 (1930s-1940s)
• Maryland Route 315 (former)
• Maryland Route 319
• Maryland Route 322 (1950s)
• Maryland Route 322 (former)
• Maryland Route 325
• Maryland Route 326
• Maryland Route 327 (former)
• Maryland Route 331 (1930s)