An email from Sarah Taylor brought the following query:
I have come across a will dated to 1693 from Much Hoole in which the testator refers to some land holdings … ‘A messuage, dwelling house, fifteen and a half acres, half a woodland and fifteen falls of land.’ After some googling I discovered that a ‘fall’, or ‘faw’ was an old unit of measurement used in Scotland and was equivalent to a pole. I wondered why a Scottish unit of measurement should have been in use in Lancashire and whether it was in common usage in the area.
The will is that of Margery Berkonsall, widow, of Little Hoole and was written on 30th July 1693 and proved 23rd May 1694. I have not seen the original, only a transcription made by another family historian which appears on their Ancestry tree – so I don’t know how accurate a transcription it is. The original is held in the Lancashire Archive reference number WCW/Infra/C1367/12.
Sarah went on to search the Lancashire Archives catalogue and discovered several other instances of the use of the Scottish unit, as in:
15 Oct 1761 Grant by Ladies of the Manor of Slaidburn to Joshua Hill of Newton cordwainer of a piece of waste land in Newton adjoining on the east to the smithy or blacksmith’s shop belonging to the said Joshua Hill and to a croft belonging to Mr Thomas Salisbury, containing 49 square yards or one fall and nine yards of land. Fine ½d. (DDKW Box 5 No. 11)
I pointed Sarah in the direction of David Hunt, curator at the South Ribble Museum, who revealed that the term ‘falls of land’ was in common use in the area.
Sarah consulted the Scottish Archives Network, and found that ‘the term “fall” comes from the Old Norse “fale” meaning pole or perch’. The network provides the following definition, ‘The basic units of area were the rood and acre. The rood (from the word rod, meaning a measuring rod) was the equivalent of 40 square falls.’ 
The next port of call was the ever-helpful people at Lancashire Archives. The use of the term had them baffled, explained archivist Keri Nicholson in an email:
In all honesty we didn’t initially have an answer to your question about Scottish land measurements, but we’ve asked Alan Crosby who was able to come up with a response for us. He says that the measurement terms you are finding aren’t necessarily specifically Scottish. They are Lowland Scots, which is itself a dialect of Northumbrian English. Apparently the English spoken north of the Mersey-Humber and south of the Forth-Clyde would actually have been very similar. So while ‘rodfall’ or ‘roodfall’ is found frequently in documents from the north-west of England it isn’t consciously Scottish and doesn’t imply a Scottish influence, it’s really an Anglian [Anglo-Saxon] dialect.
Alan Crosby is the editor of The Local Historian, the journal of the British Association of Local History, and the author of dozens of books and articles on the subject. One of those books is England’s Landscape: the North West,  which he co-wrote with Angus Winchester, a retired Lancaster University professor of history.
Angus ran a course in local history at Lancaster with Mike Winstanley that I was fortunate enough to attend a few years ago. It was that course that supplied the springboard for this website. So I turned to Angus for help. He emailed:
I think ‘fall’ is in even more widespread use than Alan suggests – it’s in the Oxford English Dictionary (= rod, pole or perch; one fortieth of a furlong). I think the term refers to the falling of a physical land rod on the ground when land was being measured. The land rod was one rod, pole or perch in length (which of course varied from the statue perch of 16.5 feet to a whole range of local measures – 24 feet in Cheshire; 21 feet ‘forest measure’ in parts of Cumbria etc).
The Oxford English Dictionary supplies the following definitions of ‘fall’:
a. Chiefly Scottish and English regional (northern). A measure of land area equal to one square fall (36 square ells), varying locally. Now historical. In Scotland, a fall was equal to approx. 343.1 square feet (31.9 square metres).
b. Chiefly Scottish and English regional (northern). A unit of length used esp. for measuring land, equal to one fortieth of a furlong, and varying according to the local length of the furlong; also called perch, pole, rod. Now historical. In Scotland, a fall was equal to 18.5 feet (approx. 5.65 metres).
†c. In marl-digging: a unit of volume equal to 64 cubic yards (approx. 48.93 cubic metres). Obsolete.
The dictionary supplies more than 20 examples of the use of the term, mostly from Scotland. All the English examples are from the North-West, with two exceptions: a very early one from Ripon and another from the Lincolnshire coast. That Lincolnshire example is from a single page in William Dugdale’s treatise on fen drainage of 1662 . That page contains the following four examples of the use of the term on the Lincolnshire coast:
one Sea-bank new made, in Skeg∣nes [Skegness], to begin at a place called Ranson hyrne, and to be xl falls in length
which new bank to be xx falls in length
And that a new Gote, or Clow, be set in Waynflet haven, within ten falls of Thorpe and Waynflet Sea-gote
and another to be set four∣score falls beneath the old Sea Gote; both to be done by the Land-holders in Waynflet
Joseph Wright’s English Dialect Dictionary, 1898-1905, provides the following definition, with examples from Scotland, including from Ayrshire and Lanarkshire, and from Lancashire:
10. The distance over which a measuring-rod ‘falls,’ esp. a square measure, gen. = 6 ells square.
Sc. 1/160 of a Scotch acre, as the perch is of the English acre, Morton Cyclo. Agric. (1863); A measure nearly equal to an E. perch or rood; including six ells square (Jam.). Ayr. It was a lang siller she wanted for the hoose and twa fa’ of ground at the back o’t, Service Dr. Duguid (ed. 1887) 118; A patch of some five or six falls of ground for a garden, Galt Sir A. Wylie (1822) i. Lnk. A fall of ground converted into drills will produce plants sufficient for transplanting 3 or 4 acres, Stephens Farm Bk. (ed. 1845) II. 68. Lan. Richard Dickinson came and took 20 falls of delving off me, Walkden Diary (ed. 1866) 103; A fall of land varies in different parts of the country. It is a square perch; statute measure it contains 30¼ square yards; seven yards measure 49 yards, seven and a half yards measure 56¼ yards; and according to the Cheshire measure 64 yards, WALKDEN Diary 30. 
I had initially taken Wright’s definition, ‘The distance over which a measuring-rod ‘falls ’ … ’ , as simple speculation. But a check on the very useful guide to Old Norse put on line by the Linguistics Research Center at the University of Texas gives the following glossary entry: ‘fall – noun, neuter; nominative singular of <fall> fall’. So Wright might have been on to something, but more expert opinion (see below) rubbishes any suggestion of an Old Norse root. And I have been unable to find anything to substantiate the Scottish Archives Network’s view that ‘the term “fall” comes from the Old Norse “fale” meaning pole or perch’
A search of the National Archives catalogue for documents containing both ‘acre’ and ‘fall’ yielded 31 examples of the use of fall as a unit of measurement. These dated from the late 13th century to 1836. They were chiefly from Lancashire, but included four more examples from Lincolnshire. This is clearly a far from exhaustive list and simply gives pointers to the use of the term. Accidental survival of documents can easily skew attempts to determine the distribution of the use of a dialectical term. For example the list of 31 examples includes eleven dealing with the same property in Manchester.
Another example is found in a charter from the early 14th century recorded in the Gormanston Register:
 Charter. The Mayor and community of the town of Preston, have granted to Roger Auward of Preston, his heirs or assigns, half an acre and thirteen perches (fall’) of meadow, with the appurtenances, lying on Auenamendis (or Aaenamedys) [? Avenham meadows] in the town of Preston: to hold of the chief lords of that fee, by the services accustomed. Grantors will warrant. Sealed by grantors with their common seal.
Dated at Preston on Friday before the feast of St. Edward the bishop, a.r. ix. Edward son of King Edward. (1315-16.)
An appeal to John Insley, emeritus professor of Heidelberg University and Lancashire editor of the Survey of English Place-Names, brought a swift and seemingly definitive response to the question of the etymology of the term:
Middle English Dictionary (MED) (Ann Arbor, 1952 ff., and online) s.v. fal gives the sense a linear measure of land shorter than a rod; also, the corresponding square measure ̔ and cites a Ripon Charter of c. 1235, the 13th-century cartulary of the Gilbertine Priory of Alvingham in Lincolnshire and the Chartulary of Cockersand Abbey in Lancashire. The Cockersand Chartulary was written in 1268 and the entry speaks of renam acram terrae et unam rodeland et quatuordecim falles terrae. MED gives the etymology as Old English feall, ġefeall, and I see no reason to question this in favour of a Norse origin. There is no evidence for the term before the thirteenth century and it may well be a Middle English innovation.
Perhaps the last word should be left to Sarah:
I’m not sure all of the above takes us much closer to answering Sarah’s initial query. What it does do, to my mind, is show how satisfying local history research can be. As Sarah commented in an email, ‘…finding one small detail has sparked such an interesting journey of discovery’.
Some years ago I attended a conference at Lancaster University at which a retired history professor, I think he was from Durham University, made a plea for more attention to be devoted to producing transcripts of original records. If I remember rightly, he pointed out that the unearthing of original records can demolish the foundations on which a host of university theses and dissertations are raised.
Lancashire Archives contains a wealth of such original records just waiting to be transcribed. A good example of what can be achieved is the work of David Berry in transcribing all of Preston’s surviving court leet records from 1653 to 1813.
* A related matter is the variation in the size of acres throughout Lancashire from medieval times and into the 19th century. See Lancashire Land Measurement.
 ‘Scottish Archive Network – Scottish Weights and Measures Guide (Distance and Area)’, n.d., https://www.scan.org.uk/measures/distance.asp.
 Angus Winchester and Alan Crosby, The North West: English Heritage Volume 8 (London: Collins, 2006).
 William Dugdale, The History of Imbanking and Drayning of Divers Fenns and Marshes, Both in Forein Parts and in This Kingdom, and of the Improvements Thereby Extracted from Records, Manuscripts, and Other Authentick Testimonies / by William Dugdale. (London: Printed by Alice Warren, 1662; published online by the Text Creation Partnership, n.d.), 165, http://name.umdl.umich.edu/A36795.0001.001.
 ‘EDD English Dialect Dictionary Online’, n.d., http://eddonline-proj.uibk.ac.at/edd/index.jsp.