Irnham is a village and civil parish in the South Kesteven District of Lincolnshire. It is situated approximately 10 miles (16 km) southeast from Grantham. To the north is Ingoldsby and to the south-west, Corby. The village is on a high limestone ridge that forms part of the Kesteven Uplands.
The civil parish of Irnham includes the hamlets of Bulby and Hawthorpe.
Irnham Hall was the ancient seat of the Paynells and from about 1200, the Luttrell family, Lords of Irnham until 1418. The Manor then passed by marriage to the Hilton family and similarly in 1510 to the Thimbleby family, by whom the present Tudor house was built in about 1600. In 1430, Godfrey Hilton, a knight, was residing in "Irenham".
In 1853 William Hervey Woodhouse (d. 1859), who married Sarah Elizabeth Cole, bought the Hall, which had several further owners until purchased in 1901 by the present owners, the Benton Jones family.
Lincolnshire is very low-lying and land had to be drained for agriculture to be successful. The larger drainage channels, many of which are parallel to each other, became boundaries between parishes. Many parishes are long and thin for this reason.
There is much fenland in Lincolnshire, particularly in the Boston and Horncastle areas. Fenlands tended to be extraparochial before the mid 1850s, and although many sections were identified with names and given the title "civil parish", little information has been found about them. Many appear to be abolished in 1906, but the parish which adopts them is not given in A Vision of Britain through Time. Note the WR category Lincolnshire Fenland Settlements which is an attempt to organize them into one list.
From 1889 until 1974 Lincolnshire was divided into three administrative counties: Parts of Holland, Parts of Kesteven and Parts of Lindsey. These formal names do not fit with modern grammatical usage, but that is what they were, nonetheless. In 1974 the northern section of Lindsey, along with the East Riding of Yorkshire, became the short-lived county of Humberside. In 1996 Humberside was abolished and the area previously in Lincolnshire was made into the two "unitary authorities" of North Lincolnshire and North East Lincolnshire. The remainder of Lincolnshire was divided into "non-metropolitan districts" or "district municipalities" in 1974. Towns, villages and parishes are all listed under Lincolnshire, but the present-day districts are also given so that places in this large county can more easily be located and linked to their wider neighbourhoods. See the WR placepage Lincolnshire, England and the smaller divisions for further explanation.