There are almost a thousand cities in Poland, including many riverside cities, which in scientific works are most often described and analysed separately, as an individual subject of research. The aim of the article is to highlight the features and compare all cities located by the longest Polish rivers, i.e. those that are over 250 km long. There are 188 of such cities. They include the largest Polish cities, led by Warsaw, and small towns, including the smallest one, namely Opatowiec. Some of these towns were built in ancient times (Racibórz), many emerged in the 13th century, while the youngest one, Łomianki by the Vistula River, became a city only in 1989. Over 480 road and railway bridges were built there, which enable efficient connections between the banks. They also include most of Poland’s capitals of the regions, although as many as 105 of them are the capitals of urban-rural communes. They were researched using data available on the Google Maps geoportal, data from the Local Data Bank, the official websites of municipal offices, and the results of several interviews. The effects provide structured knowledge about the functioning of the most important Polish riverside cities.