The Mokelumne River, out in the valley, on the way back from my aunt’s house in Sutter Creek a couple months ago. Oddly enough, there are actually very few rivers in the SF Bay Area… it’s mostly fed by the Sacramento River, and that’s way northeast of where I hang out.
The Mississippi River, about half an hour ago.
I haven’t been out of town in the past week, but the last river I crossed was the Kentucky River. I grew up at the confluence of the Kentucky and Ohio Rivers and crossed both frequently growing up, as well as the Little Kentucky, Licking and Cumberland rivers. The last sort of major waterways I crossed was the Tennessee and and Cumberland rivers, which run parallel to one another, and were dammed to make Lake Barkley and Kentucky Lake, which bound the region known as the Land Between the Lakes. Further on, the Cumberland is also dammed to make Lake Cumberland; further yet is Cumberland Falls, the “Niagara of the South.” Impressive river! I haven’t crossed the Mississippi in years, but it is pretty impressive, too, yo. 
I crossed the Susquehanna yesterday, but I try not to.
I crossed the Wabash river this past weekend. It’s only a few miles from where I live.
But what can you do? Everyone knows how overly sensitive the Susquehanna can be.
Fox
I cross the South Fork of the Coeur d’Alene River at least 12 times each week.
The Puyallup River in Tacoma a few days ago. Will be crossing it again today.
The last time I crossed the Little Pigeon River was about a week ago.
The Sangamon. We live quite near the bottoms. I cross it on my usual walking path, also whenever I want to go into town.
I cross about a dozen branches of the Milwaukee river on my way to work.
Say, did you hear about the priest that crossed a river?
Did the waters of the Jordan dry up so the Israelites could enter the Promised land?
The Rio Grande. It’s about 5 miles east of where I live and most of Albuquerque is on the other side so I cross it every week or two.
A couple of weeks ago I visited the Rio Grande Gorge Bridge just west of Taos with some family members.
I crossed the north branch of the Chicago River about six or seven times today.
The River des Peres (really a big drainage canal)…every day.
As I live in St Louis metro area crossing rivers is a typical occurance; I cross the Mississippi, Misouri, Merimack quite frequently.
The Harlem River, rounding out the “Rivers that bound Manhattan” crowd.
The Little Tallapoosa is right up the road and I cross it everytime I go to town. It’s more of a creek, but darn it it’s called a river so it counts.
The south fork of the Snake River, earlier this afternoon (in a sailplane).