The Roman Map of Britain Croucangusto or Croucingosto? Low Borrowbridge, Grayrigg, Westmorland
Stodoion (R&C 158)
The next fort south on Margary 7d from Brougham Brocara (R&C 156) is Low Borrowbridge at the junction of Borrow Beck with the River Lune. Borrow Beck's old name Burgra 1198 is from ON borgará 'stream by a fort'. The northern branch of Borrow Beck is Crookdale Beck Crookesdale, wherein crouc- survives.The -ingo looks like Welsh yng 'narrow', presumably substantivized. The valleys of the above-named rivers at this point are particularly steep, thus 'Crouc-narrow(s)' accurately describes the site of the fort.
And just when things looked fairly settled, I realize that the first three letters of the next entry are Sto from Stodoion (R&C 158). I'd originally guessed that Sto was an abbreviation for statio 'post, station', but this makes a very attractive Croucingosto where -ingosto (as angusto) is 'a narrow place', rather than 'narrows'. The fom angusto is the ablative/dative of angustum (subst. of the adj. angustus 'narrow').
See Coates and Breeze  Aust and Ingst, Gloucestershire pp 54-7, where Ingst is treated as a borrowing from Latin angustiĉ as a Brittonicized *engyst. See also Richard Coates with David Horovitz and Stephen Potter on Ingestre, Staffordshire.
There is, of course, the distinct possibility that ingosto represents an unrecorded British word related to yng.
Low Borrowbridge NY6001
LOW BORROWBRIDGE ROMAN FORT