Mt. Lemmon, outside Tucson, AZ.

Distance: 29 Miles
Starting elevation: ~3,000'
Ending elevation: ~8,950' (observatory gate)
Ascent: 6500'
Avg. grade: ~5-6% (ignoring a ~2 mile downhill section at about the 21 mile mark)
Max grade: >10% (between ski valley & the observatory)