4121 Carlin is a main belt asteroid with a perihelion of 1.7705672 AU. It has an eccentricity of 0.2545254 and an orbital period of 1336.1440360 days (3.66 years). Carlin has an average orbital speed of 19.33049096 km/s and an inclination of 23.10272°.
The asteroid was discovered on May 2, 1986 at the Palomar Observatory.