My surname is Holland and my family has always spelled it with a double L. hope this helps you:
History And Origin
1. Irish: reduced Anglicized form of Gaelic Ó hÓileáin, a variant of Ó hAoláin, from a form of Faolán (with loss of the initial F-), a personal name representing a diminutive of faol ‘wolf'. Compare Whelan.
2. English and Scottish: habitational name from Holland, a division of Lincolnshire, or any of the eight villages in various parts of England so called, from Old English hōh ‘ridge' + land ‘land'. The Scottish name may also be from places called Holland in Orkney, Houlland in Shetland, Hollandbush in Stirlingshire, and Holland-Hirst in the parish of Kirkintilloch.
3. English, German, Jewish (Ashkenazic), Danish, and Dutch: regional name from Holland, a province of the Netherlands.
Dictionary of American Family Names, Oxford University Press, Inc. © 2006 Patrick Hanks
After centuries of use, surname spellings may have varied drastically over time. This may be the result of an intentional or unintentional change made by your ancestors. It means you should incorporate typical surname variants or misspellings into your ancestor search, to ensure you don’t miss an important piece of the puzzle. Here are some common Holland surname variants:
Soundex: Haaland, Hailand, Hailend, Hailu Mitiku, Halamitschek, Halamoutis, Halamuda, Haland, Halanda
Metaphone: Haaland, Hailand, Hailend, Haland, Halanda, Halandae, Halander, Halandras, Hale Andrews