I have been playing the latest snapshots for the past several months. Until today, I have not had any issues with the game crashing. Today, I consistently encounter a crash upon moving to a certain area on the map. 

When I experienced the initial crash, I was riding a horse (with diamond armor), and upon reaching the approximate coordinates X= -857 Y= 78 Z=-256, the game simply crashed.

Upon relogging the first time, I appeared a few hundred blocks east of where the crash occurred. When arriving at the above-mentioned approximate coordinates, the game crashed again. When relogging again, the horse had disappeared.

I have since relogged several times, and the game crashes each time.

While I have opted to send automatic crash logs to Mojang, unfortunately, I'm unsure where to locate these logs on my computer. Hopefully, your team can find the relevant details and correct this issue.