In the 12th century, the O'Briens, the Kings of Thomond, left their seat of power in Limerick and built a Clonroad Fort in 1210, a royal residence on the banks of the Fergus.

In 1240, following the arrival of Franciscan monks, King Donnchadh O'Brien ordered the construction of an extensive church which he later donated to the Friars.

Despite its official closure in 1540, the Friary continued to operate in a limited way until 1690, remaining the last school of Catholic Theology to survive the Reformation.

When Clare became a county under the rule of Elizabeth I in 1586, Ennis was chosen as its administrative centre and capital because of its central location and its association with the Earls of Thomond.

Ennis received a grant to hold fairs and markets in 1610 and later a Charter for a Corporation with a Provost, Free Burgesses, Commonalty and a Town Clerk.

The Clare Road and Clonroad areas contain terraced cottages built in the early 20th century to house soldiers.

Over the centuries the market town slowly expanded, and eventually developed as a small manufacturing and distribution centre with commodities moved by river to the port at Clarecastle for shipping abroad.

A monument to Éamon de Valera, founder of the party and former President of Ireland, stands outside Ennis Courthouse.

At one time, small sailing boats made their way up river from the Shannon and berthed in the centre of the town at Woodquay.

[16] The town centre consists of medieval narrow streets and laneways, overshadowed by structures built over the last thousand years.

Ennis also includes many relief organisations, such as The Samaritans, Clare Care and St. Vincent De Paul.

Situated 14  km from Shannon Airport, Ennis is served by both bus and rail links to all major cities and towns in Ireland.

Ennis railway station is on the Clon Road toward the east of the town, which links to the main N18 in either direction.

Bus services are provided to Shannon Airport, Galway, Limerick, Cork, Dublin and all routes in between and run nearly every hour.

The Ennis Book Club Festival, in association with Clare County Library, runs annually on the first weekend in March.

Ennis has numerous football clubs (soccer, GAA and rugby) that play in various leagues from schoolboys to senior.

The Lees Road Sports and Amenity Park, 1  km from the town centre, is set in 134 acres (54 ha) of wood and parkland.

The project also gave Ennis Ireland's first high-speed ISDN line infrastructure, which connected all the town's businesses together.

In 2012, 2013 and 2021, Ennis won the Irish Tidy Towns Competition in the Large Urban Centre category.

[31] The town of Ennis is situated in parts of the civil parishes of Doora, Drumcliff, Kilraghtis and Templemaley.