26.2 miles @ ~11:30 min/mi

See Washington Birthday Marathon 2006 for a report on this frigid frolic through the forests of the Beltsville Agricultural Research Center and nearby Greenbelt, Maryland. My "official" finishing time is a hair over 5 hours, but by my watch I made it across the line in 4:59:58. Moving clocks run slower, according to Einstein's Special Relativity, but at my pace that effect only accounts for half a picosecond.