The old Murphy-Dolan Store, which was built in 1874, later became the Lincoln County Courthouse. In 1881, Billy the Kid was being held prisoner there. He stole a gun, killed the guards and escaped. According to some versions, he made his departure even more spectacular by hanging around town for an hour or so chatting to acquaintances. Although you can't make out the sign in my photo, the Sheriff's Office is located upstairs.
So much has been written about Billy the Kid that I will leave you with some links to get started so that you can explore his life as much as you want.
About Billy the Kid includes little known facts, a biography, a filmography, maps, letters, interviews, a gallery of photos and art work, and more.
Billy the Kid, Quien Es? Great video from New Mexico Public Broadcasting, originally broadcast by KNME: Part 1, Part 2, and Part 3
The Lincoln County War is a well-documented account of what happened in Lincoln County during 1878-1879.