In the northeast are the Slievefelim Mountains. In the west, the land rises to a low plateau towards the Kerry border, with the Mullaghareirk Mountains to the south. Some of these upland areas have been planted with forest, these parts of limerick are popular with hill walkers.

Limerick City is the centre of the transport system, the city has a railway connection to Limerick Junction in Tipperary, where it meets the Dublin to Cork line. This line then passes through the southeast of County Limerick. There is a branch line to Nenagh and a freight only line to Foynes serving the port. County Limerick receives most of the shipping on the west coast of Ireland, the ports are the harbour of Limerick City and the deep water ports of Foynes and Aughinish on the Shannon estuary. The proximity of Shannon airport which handles international flights, has considerably benefited Tourism City and surrounding areas. The national primary roads that radiate from the city within the county are the N7 to Dublin, the N24 to Waterford, the N20 to Cork, and the N21 to Tralee.

Limerick City has many thriving Industries, almost half of industrial employment is in light engineering. These includes electronic engineering, household appliances and other electrical goods, machinery and metal goods, also medical and optical supplies. The computer industry has in recent years become a major employer. Food processing, is also an important contributor to the economy. It includes bacon and other meat products, dairy processing, and milling. Other industry's produce building materials, chemicals, clothing, furniture, wood products, and plastic goods, as well as printing and publishing. There are two other major industrial plants, one making cement near Limerick city and the other producing alumna at Aughinish on the Shannon estuary. Limerick lace is one of the traditional industries which still survives although on a much reduced scale.

The agricultural industry employs about 17% of the workforce, most farms are of medium size, averaging about 25 hectares in size. The most fertile area of the county is often referred to as 'The Golden Vale' it is situated in the center and east of the county, the soils are best suited to grass and only 1 per cent of the land is under arable crops. The rest used mostly for dairy and beef farming In the west the land is less fertile some sheep are reared there.

Many people who live commute to work on the Shannon industrial estate and airport in County Clare. Service industries employ for over half the workforce. The city is the major service centre for the Midwest region. These services include catering, education, finance, health, public administration, retail and wholesale distribution, and transport.

The University of Limerick was formed in 1989 from the National Institute of Higher Education. There are also third-level (higher education) colleges for art, business, education, music, and technology.