Longford is a county in the province of Leinster, the name comes from the Gaelic Longfort (the fortress).The county is mainly rural, and Longford is its only large town. Bounded on the north-west by Leitrim, on the north-east by Cavan, on the south-east by Westmeath, and on the west by Roscommon from which it is separated by Lough Ree. The River Inny flows through the county. Longford has an area of 1,044 sq km (403 sq MI). The maximum dimensions are 45 kilometers from north to south, and 35 kilometers from east to west. Most of Longford is lowland, which rises gently from the River Shannon, with isolated hills. The underlying rock is limestone, with some slate and shale in the north. Most of the land is farmed, and about a fifth is bog land. More than a quarter of the working people have jobs in agriculture. Almost all the farmland is under grass, with beef cattle and milk accounting for three-quarters of the agricultural output. There are several modern industries, and manufacturing now accounts for one-fifth of employment. Textiles and clothing are the leading industries. Half of them are town. County Longford from Samuel Lewis' Topographical Directory of Ireland 1837

There is a peat-fired power station at Lanesborough on the River Shannon which uses peat from the county's bogs. Some areas of bog and wet soils have been planted with pine trees for timber production.

The county borders lough Ree in the west and offers some excellent angling, salmon, trout, bream, tench, and roach can all be caught in the county's rivers and lough's.

The 18th century playwright and poet Oliver Goldsmith was born in Pallas near Ballymahon, and the county has many associations with him: there is an interpretative centre in Glassan. Carriglas Manor, near Longford town, is the finest stately home in the county and was built in 1857 in the then-popular Neo-Gothic style. It contains the original furnishings and a costume collection, and there is extensive surrounding parkland. Granard, which has the remains of a motte-and-bailey castle built in 1199, holds a famous harp festival every August.

Lough Ree contains the islands of Inchbofin and Inchclearaun on which are archaeological ruins from the early Celtic Church. The islands are also associated with the mythological figure of Medb (Maeve) an Irish warrior queen, also known as Queen Mab.

Before and after the famine many people in search of a better life emigrated to North America, Australia and Britain, between the years of 1842 to 1860 a considerable number of people from Longford chose Argentina. Many of them settled in Buenos Aires. Edel Miro O'Farrlell who became the president of the Republic of Argentina in 1914 was a kinsman of one of these early emigrants.