The maximum length of Hertfordshire, along a line running in a south-westerly and north-easterly direction, is about twenty-eight miles; while its greatest breadth, along a line passing near its centre from the neighbourhood of Tring to that of Bishop’s Stortford, is very nearly the same. Owing to its extremely irregular outline, the county has, for its size, a very large circumference, measuring approximately 130 miles. Here it should be stated that the ancient area of the county differs somewhat from that of what is now known as the administrative county. According to the census of 1901, the area of the ancient, or geographical county, included 406,157 acres, whereas that of the administrative county is only 404,518 acres[1], or about 630 square miles. The difference in these numbers is due to the fact that certain portions of the old county, such as that part of the parish of Caddington originally included in Hertfordshire, have been transferred to adjacent counties. The figures relating to population, etc. given in the sequel refer to the administrative county.

In size Hertford may be reckoned a medium county, its acreage being rather less than that of Surrey, and about half that of Essex.

To describe the shape of Hertfordshire is almost an impossibility, on account of its extremely irregular contour; but as its two maximum diameters are approximately equal, it may be said to lie in a square, of which the four angles have been cut away to a greater or less extent in a curiously irregular manner. The reason of this irregular outline, seeing that only the eastern border is formed to any great extent by a river-valley, is very difficult to guess. Where its south-eastern boundary leaves the Lea valley in the neighbourhood of Waltham Abbey, Middlesex gives off from Enfield Chase a kind of peninsula running in a north-westerly direction into Hertfordshire; while, in its turn, Hertfordshire, a short distance to the south, sends a better-marked and irregular peninsula (in which stands Chipping Barnet) jutting far into Middlesex. In consequence of this interlocking arrangement, a portion of Hertfordshire actually lies to the south of a part of Middlesex, although, as a whole, the former county is due north of the latter. Another, but narrower, projection runs from the south-western corner of the county in the neighbourhood of Rickmansworth so as to cut off the north-western corner of Middlesex from Buckinghamshire; while a third prominence, in which Tring is situated, is wedged into Buckinghamshire from the western side of the county. Other minor projections occur on the north-western and northern border, of which the most pronounced is the one north of Baldock, jutting in between Bedfordshire and Cambridgeshire.

As regards boundaries, Hertfordshire is bordered on the east by Essex, by Middlesex on the south, by Buckinghamshire on the south-west, by Bedfordshire on the north-west, and, to a small extent, by Cambridgeshire on the north. From a short distance below the Rye House to Waltham Abbey the boundary between Hertfordshire and Essex is a natural one, formed by the rivers Stort and Lea; but the other boundaries of our county are, for the most part at any rate, purely artificial.

It should be added that these boundaries at the present day do not everywhere accord with those of half a century ago. The parish of Caddington was, for instance, in former days partly in Hertfordshire and partly in Bedfordshire, but under the provisions of the Local Government Act of 1888, confirmed in 1897, the whole of it was included in the latter county. Certain other alterations were made about the same time in the boundary.