The problem of the reflection of current at the end of a semi-infinite wire is solved using Wiener-Hopf techniques. It is found that the end effect can be expressed as a single reflection parameter which is a function of the height of the wire, the electrical properties of the earth, and the frequency of the excitation. This simplification yields an accurate representation for the reflected current for points not very close to the end of the wire. Representation of the end effect in this manner leads to a simple theory for long finite horizontal antennas similar to that found in transmission line problems. Input conductance changes as a function of earth parameters for a resonant and an antiresonant antenna are then presented.