Check Overseas Records (Including Scotland And Ireland)
Although people didn’t travel abroad as often as they do now, when they did go, they would often stay longer, leaving a record trail if you’re lucky. Familysearch. org is a handy one-stop shop for checking a range of overseas censuses, including Scotland up to 1891 (the Scottish censuses can also be searched on ancestry.co.uk and findmypast.co.uk.
Irish censuses for 1901 and 1911 can be searched at census. nationalarchives.ie.
Did your relative move to Glasgow?