26 miles, but only once. (I was scouting new territory.) I've just found it's really not necessary most of the time. If I'm spiking out I typically try to push back about 5 miles and circle back to base camp the next day. If I'm walking in, I'll typically hike into an area I want to hunt from about 4am-6am for about 4 miles if there's a decent trail, hunt a few miles through that area, then after legal light ends, hike back.
n.b. I hunt Colorado, which has plenty of wilderness areas but even when in those it's hard to get more than 10-15 miles from "any" road or private property. So I've just found super-long hikes aren't really needed. The "hunt from base camp" crowd usually hangs out a few miles in, at most. And the horseback crowd is usually 10-15 miles back. I hunt the "donut hole" between them.