Maresme (Catalan pronunciation: [məˈɾɛzmə]) is a comarca (county) in the Barcelona region in Catalonia, located along the Mediterranean coast, between the comarques of Barcelonès (at the Southwest) and Selva (at the Northeast), and also bordering with Vallès Oriental (at the west).

Maresme occupies a long and narrow area between the Mediterranean Sea and the hills of Serralada Litoral (Catalonia's coastal mountains), and specifically Montnegre's and Corredor's hills in the northern half and Sant Mateu's hills in the southern half.

Probably the main distinct elements of its geography are the characteristic rieres (torrents).

These short, intermittent streams, which cross the comarca transversally about every hundred meters, produce powerful and dangerous floods when it rains.

Maresme has been historically very well connected with the rest of the comarca as well as with Barcelona by the old Camí Ral (Royal Way) (current N-II main road) and railroad (The Barcelona–Mataró railroad route, finished in 1848, was the first ever in all the Iberian Peninsula).