4.5 miles each way - Up on the Pocono Plateau, PA. There are some scary drivers up here!
A hair over 8 miles in Atlanta, GA
I do a multi-modal commute (sort of to avoid some busy roads with no paved shoulders and 55 mph speed limit). 6 miles to the bus stop and then 4 miles from the bus to work.
3 miles one-way. First mile down 25mph surface streets devoid of traffic and freshly paved, last two miles down a well-lit mup. Do it everyday, rain or shine, sometimes repeatedly. Thankfully I live in Chico, CA so it's usually shine. The 10-day forecast sucks right now though and my wet-weather ride is at the shop.