The Whitewater River Run Preserve Boundary in the Lance Rosier Unit to Confluence with Pine Island Bayou is a popular river run located in the state of Texas. The ideal streamflow range for this river run is between 400-800 cfs, with the best time to visit being in the spring or fall. The class rating for this river run is Class II-III, with some Class IV rapids in certain sections. The segment mileage for this river run is approximately 11 miles.

There are several specific river rapids and obstacles on this river run, including the "Pinball" rapid, which is a Class III rapid with multiple channels and boulder gardens. Other notable rapids include "Satan's Staircase," "Little Niagara," and "The Chute." There are also several large boulders and fallen trees that create challenging obstacles for kayakers and rafters.

There are specific regulations that apply to this area. The river run is located within the Big Thicket National Preserve, and as such, visitors must follow all rules and regulations set forth by the National Park Service. Visitors are also required to obtain a permit before using the river run. Additionally, visitors must abide by Leave No Trace principles and pack out all trash and debris.

Overall, the Whitewater River Run Preserve Boundary in the Lance Rosier Unit to Confluence with Pine Island Bayou is a challenging and exciting river run that is popular among kayakers and rafters. With its fast-moving rapids, challenging obstacles, and beautiful scenery, it is a must-visit destination for any outdoor enthusiast.