Abstract: The ages of M dwarfs in the field of the galaxy are challenging to determine; consequently, the evolution of rotation and magnetism is difficult to investigate observationally. In my current research, I am exploring two questions: 1) What determines the longest spins M dwarfs can have? And 2) Do M dwarfs undergo an era of rapid angular momentum evolution? I will share my method for measuring stellar rotation periods and the new periods I've measured, and I will discuss what these data tell us about spin-down in M dwarf stars.