Chris said Yuba City... That town is as flat as a pool table. Yes Sutter Buttes is the world's smallest mountain range, but the road circles the bottom where it is flat and smooth.
I live up in Penn Valley about 30 miles from the Buttes and we have wee little hills... in fact I always wonder what guys mean when they say their bikes cruise at 45 mph. I don't have any flat level places to test my bike out here... I go up to 40 or so mph, but that is downhill.... lots different from Yuba City, Marysville flat. Their biggest hill is the bridge over the river!