Farrah was a grocer and an amateur botanist, who went on to become a Fellow of The Linnean Society and chairman of Yorkshire Naturalists' Union.

Farrah said that although Grainge was born at Dishforth on 25 January 1818 his parents (farmer Thomas Grainge (c.1771 – Stokesley 1841 or 1845)[nb 1] and Elizabeth Chapman (Hutton Rudby c.1778 – Ripon 1867))[2][nb 2] had taken over the family property, Castiles Farm near Kirkby Malzeard, by the following March.

Grainge attended Kirkby Malzeard village school, leaving at age 12 to work on the farm for fifteen years.

[nb 4] In 1845, at the age of 27 Grainge became clerk to Boroughbridge solicitor Mr Hirst (later Hirst & Capes), remaining there for fourteen years and producing his first publication, The History of Aldborough and Boroughbridge, in 1853, although he was not credited as author, because "his modesty would not permit of it".

[nb 10] However, according to Farrah, in 1860 Grainge opened a shop in Baker Lane (later Walker Road) in Harrogate, selling books and stationery.

Grainge was a practical and outdoor antiquarian and naturalist, and took John Farrah under his wing as a student and assistant:[4] [They] tramped together hundreds of miles ... Mr Grainge possessed the happy knack of drawing persons into conversation when he took his long journeys on foot.

[14] The painting was presented to Harrogate Field Naturalists' and Camera Club in the late 1890s by John Farrah.

Farrah described it thus in 1895:[4] Castiles is the site of a military camp, and is one of the largest British earthworks to be found in Yorkshire; here Mr. Grainge spent the first 27 years of his life.

He surveyed and studied every detail of these extensive earthworks,[4] eventually drawing a plan, explaining every portion.

The writing of [his] books entailed an amount of labour, mental and physical, which few men were capable of; all the matter was collected by himself exclusively; parish registers and other documents were searched most carefully, and thus a large number of interesting facts was unearthed and rescued from oblivion.

[4]Although, according to Farrah, Grainge saw Castiles as a military camp, saying it also "bore evidence of having been the scene of Druidical worship",[5] today's archaeologists see it differently.

The site is now damaged, but it had a "central circular rampart of stone surrounded by a large irregular area, enclosed by a trench".

[17] There is no public access, but "25 earthfast boulders and a boundary ditch" can be seen over the wall near Castiles farm house, from the Laverton–Pateley Bridge road.

[18] It is possible that Grainge mistook a settlement with a rampart for a military camp, however just under 2 miles (3.22 kilometres) to the west of Castiles is Fortress Dyke, described as "a probable Iron Age/Romano-British square enclosure surviving as an earthwork", and Farrah - a naturalist, not an antiquarian - may have conflated the two sites.

[19][20][nb 13] Grainge is likely to have visited Fortress Dyke, because while at Castiles "alone he explored all the valleys, woods, glens and ravines within half-a-dozen miles of his home".

[22] The West Somerset Free Press said:[23] One of the little regarded but invaluable company of local historians has been removed by the death of Mr William Grainge, of Harrogate, at the age of 77.

[4]Besides the above publications, Grainge left a number of manuscripts and lecture-notes, and partial histories of villages of the North Riding of Yorkshire.