| Montsià | |
| Native Name Lang: | ca |
| Settlement Type: | Comarca |
| Subdivision Type: | Country |
| Subdivision Name: |  Spain |
| Subdivision Type1: | Autonomous community |
| Subdivision Type2: | Region |
| Subdivision Name2: | Terres de l'Ebre |
| Subdivision Type3: | Province |
| Subdivision Name3: | Tarragona |
| Seat Type: | Capital |
| Seat: | Amposta |
| Leader Title1: | Body |
| Leader Name1: | Montsià Comarcal Council |
| Leader Title2: | President |
| Leader Name2: | Sergi Guimerà (PSC) |
| Parts Type: | Municipalities |
| Parts Style: | list |
| P1: | Alcanar, Amposta, Freginals, La Galera, Godall, Mas de Barberans, Masdenverge, Sant Carles de la Ràpita, Sant Jaume d'Enveja, Santa Bàrbara, La Sénia, Ulldecona |
| Area Total Km2: | 735.5 |
| Population Total: | 69,613 |
| Population As Of: | 2014 |
| Population Density Km2: | auto |
| Population Demonym: | |
| Blank Name Sec1: | Largest municipality |
| Blank Info Sec1: | Amposta |
| Timezone1: | CET |
| Utc Offset1: | +1 |
| Timezone1 Dst: | CEST |
| Utc Offset1 Dst: | +2 |
| Postal Code Type: | Postal code |
| Area Code Type: | Dialing code |
Montsià (pronounced as /ca/) is a comarca (county) of the Terres de l'Ebre region, in Catalonia (Spain). It is the southernmost comarca and its capital and largest city is Amposta.
Almost all Montsià municipalities are part of the Taula del Sénia free association or mancomunitat (commonwealth).
| Municipality | Population(2014)[1] | Areakm | |||
|---|---|---|---|---|---|
| align=right | 9,637 | align=right | 47.1 | ||
| align=right | 21,197 | align=right | 138.3 | ||
| align=right | 405 | align=right | 17.6 | ||
| align=right | 800 | align=right | 27.5 | ||
| align=right | 673 | align=right | 33.6 | ||
| align=right | 619 | align=right | 78.8 | ||
| align=right | 1,106 | align=right | 14.6 | ||
| align=right | 15,003 | align=right | 53.7 | ||
| align=right | 3,555 | align=right | 60.8 | ||
| align=right | 3,821 | align=right | 28.2 | ||
| align=right | 5,893 | align=right | 108.4 | ||
| align=right | 6,904 | align=right | 126.9 | ||
| • Total: 12 | align=right | 69,613 | align=right | 735.5 |