Maps from this period almost exclusively use engraved lettering, not type. For a digital typeface, see MVB Sirenne, a font family inspired by 18th-century engraved lettering and shares a lot characteristics with this style. You’re on your own for the looped ‘l’, however. That’s a peculiarity of this particular engraver and it’s not common in roman (upright) type.
On a hunch, I checked out the glyph map—there is an alternate looped l in MVB Sirenne.
Hah! That’s actually a mathematical symbol or alternate form for “litre”. But sure!
Because it’s meant to be used with numbers it doesn't space or look the way you’d expect an ‘l’ to look.
Circa 1800, all the type on this map would have been hand engraved, not typeset.
This site specializes in historical map fonts, but a quick look through their offerings didn’t turn up anything that contained that looped l.