Woltjer is an impact crater that is located in the northern latitudes of the Moon's far side.

This is a relatively recent impact compared to most of the craters on the far side, and the rim is still well-formed with little erosion.

The interior floor has two lines of low ridges that begin in the southeast and curve up to the northwestern inner wall.

The crater was formally named by the IAU in 1970 after Dutch astronomer Jan Woltjer.

[1] By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Woltjer.