Abstract: The Automatic Identification System (AIS) shares vessel position information for navigational safety purposes. AIS broadcasts are received by other ships and terrestrial stations; however, in some areas there is no, or low, terrestrial station coverage to receive broadcasts. The US Army Corps of Engineers (USACE) developed an Online Travel Time Atlas (OTTA) to process AIS data and derive a transit count. This study examined OTTA output from 2020 and 2021 to identify areas of high or low AIS coverage along the Upper Mississippi, Illinois, and Ohio Rivers. Segments with a yearly average of two or more transit per day were classified as high coverage, those with less than a yearly average of two transits per day were classified as low coverage. Rivers were segmented using the USACE National Channel Framework reach boundaries. Results based on calculated vessel transits were as follows: Upper Mississippi River: 837.4 miles (98%) had high coverage, with 17.4 miles (2%) of low coverage; Illinois River: 190.5 miles (59%) had high AIS coverage, and 133 miles (41%) had low AIS coverage; Ohio River: 644 miles (66%) had high coverage, and 337 miles (34%) had low coverage. AIS coverage could be improved by raising antennae heights, installing repeater equipment, or adding towers.