The Rahanweyn (Maay: Reewin, Somali: Raxanweyn, Arabic: رحنوين), also known as the Digil and Mirifle (Somali: Digil iyo Mirifle) is a major Somali clan. It is one of the major Somali clans in the Horn of Africa, with a large territory in the densely populated fertile valleys of the Jubba and Shebelle rivers and the areas inbetween, which are mainly inhabited by settlers from the Digil and Mirifle lineages.

Anthropologists and northern Somalis have helped coin the term Rahanweyn. The name is said to be a combination of Rahan (grindstone) and Weyn (large) which means (large grindstone) suggesting the name's semantic relation to the Reewin economy. Another more interesting term is said to combine the names of Rahan (crowd) and Weyn (large) which means (literally 'crowd-big' or the large crowds) indicating that the Reewin clans are a confederation of diverse Somali clans that migrated elsewhere.

However, all these definitions are based on the Northern Somali dialect rather than the southern Somali dialect therefore these definitions should be deemed inaccurate.^{[citation needed]} The name is correctly pronounced Reewin which can be divided into Ree (family) and Wiin (old) which means (old family). This name is a reference to the Reewin ancient origins which might indicate that they might have been the first Somali group to migrate to modern-day Somalia whilst the rest of the Somali clans slowly began to diverge and develop their own unique distinct dialects. Another theory states that the name Rahanweyn derives from the name of the ancestor of all Rahanweyn clans, one Ma'd or Mohammed Reewin.

Each of the two subclans of the Rahanweyn comprises a great number of clans and sub-clans. The Digil sub-clan mainly consists of farmers and coastal people, while the Mirifle are predominantly agro-pastoralists.

According to constitutional law, Somalis are linguistically grouped into Mai Terreh and Maxaa Tiri. The vast majority of the Somalis who speak Mai Terreh (also known as Mai-Mai or Af-Maay) are the Rahanweyn who descend from Sab, while the speakers of Maxaa Tiri (i.e. most spoken Somali) belong to other clans (Darod, Dir, Hawiye and Isaaq) who descend from Samaale. Both Sab and Samaale are believed to have been fathered by Hiil (ancestral father of all Somalis).

Rahanweyn clans contain a high number of adopted members, with British anthropologist I. M. Lewis describing the Rahanweyn as a "synthesis of old cultivating stock, and more recent and once nomadic immigrants from the other Somali clans", with almost every Somali lineage having some off-shoot living among them. This practice allows newcomers to integrate into resident clans in a pleasant manner. Furthermore, in riverine places such as Lower Shabelle or the Juba region, it adds to the complexity of lineage identity.

The clan resides in rich fertile lands in southern Somalia and lives on the banks of Somalia's two major rivers, the Shebelle and Jubba rivers. The Rahanweyn make up the majority in the southwestern regions of Bay, Bakool, and Lower Shabelle. They are also believed to be the silent majority in Jubbaland specifically in regions such as Gedo, Middle Juba, and Lower Juba. They are the second-largest clan to reside in Mogadishu. They are also found in the Somali Region of Ethiopia and the North Eastern Province of Kenya.

Reewin groups were the first Somali/Cushitic group to enter what is the southern part of modern-day Somalia, around the end of the second century B.C.