sentences:  The site commemorates the Chicago Portage, first written about by French explorers Father Marquette and Louis Joliet during their use of the portage and exploration of the area between Lake Michigan and the Mississippi River.The portage crossed what was known as Mud Lake, which could be wet, swampy, frozen, or dry, depending on the season, and which has since been completely obliterated.Mud Lake extended roughly from the historic western end of the South Branch of the Chicago River (near today's Damen Avenue) to the Des Plaines River at the present National Historic Site.