My typical route is about 12.5 miles one way, in the summer I sometimes go a different way and stretch it to 15 miles. I may be doing that every day soon as the other route is about to have construction on it that will last 2 or 3 weeks at least.

I have a route that's 10.5 miles but it's over 4 miles of gravel, and in the summer with the road bike with 23mm tires it's not viable.