Fed by annual snow melt, the wild Portneuf River passes through the heart of Lava Hot Springs, Idaho. This quick, rapid-filled stretch can be floated once or twice per hour.
Photo courtesy of Edgar Zuniga Jr. / Flickr

Hundreds of natural springs in the San Marcos city center feed the San Marcos River – one of the most popular tubing destinations in the state of Texas. The water remains about 72 degrees year round, making it particularly refreshing come summer.
Photo courtesy of Sean Loyless / Flickr

Floating the Guadalupe River near New Braunfels has become a Texas summer pastime. Floats last anywhere from 1 to 3 miles through the beautiful Texas Hillcountry, and the pull out is only a short drive from Austin or San Antonio.
Photo courtesy of New Braunfels

The Delaware River is one of the major rivers on the Atlantic Coast and one of the most popular waterways to float in New Jersey. The float-able portion of the river extends about 6 miles and takes about three to four hours, depending on conditions. A few Class 1 rapids add some extra fun.
Photo courtesy of Nicholas A. Tonelli / Flickr

The Shenandoah River offers a mellow tubing experience. The portion popular with tubers near Harpers Ferry takes one to two hours to float, while the stretch of the South Fork of the river near Luray, Va. takes three to five hours to enjoy.
Photo courtesy of Joshua Morley / Flickr

Missouri's Current River was the first in the U.S. to be named a a National Riverway. It's 75 percent spring-fed and float-able throughout the year, but especially appealing when summer temps rise into the 90s and 100s.
Photo courtesy of AP Photo/James A. Finley

The Tahoe area might be most famous for its lake, but the Truckee River offers aquatic adventures of its own. A leisurely float down the river extends for 3 to 5 miles, and afterward, thrill seekers can head to the Truckee River Whitewater Park to navigate 11 man-made drops over a 300-yard portion of the river.
Photo courtesy of Tahoe City Downtown Association

Cool mountain water flowing down the Green River near Asheville is the perfect prescription for a hot Carolina summer. The river alternates between peaceful stretches and mild rapids, and rope swings along the way offer a fun diversion while taking a break from the tube.
Photo courtesy of allison / Flickr

Restaurants, parks and bars are dotted all along the Yampa River as it passes through Steamboat Springs, making it easy to customize a float trip to just about any length. This family-friendly float has a few small rapids and rock features to add to the thrill.
Photo courtesy of Thinkstock

Visitors to Harpers Ferry in West Virginia have a few river options to float. Adrenaline junkies go for the Potomac River, where Class II and III rapids carry them down one of the most scenic stretches of the river in Potomac River Cap and Harpers Ferry National Park.
Photo courtesy of Glen Mazza / Flickr