Ryan originally wrote react-router but then it became part of the ReactTraining org. Ryan later left ReactTraining to do his own thing, and started reach.tech,

Ryan originally wrote react-router but then it became part of the ReactTraining org. Ryan later left ReactTraining to do his own thing, and started reach.tech, and Reach Router was born. Now Ryan is back at ReactTraining, and we’ll see what that means for the routers. FWIW, I use Reach Router for everything now and greatly prefer it.