A Loyalist is any person who is loyal to their allegiance (especially in times of revolt). During the American Revolution in what was to become the United States of America, a Loyalist (also called UEL - United Empire Loyalist) was anyone who remained loyal to the King of England. They were called Tories in their own country but Loyalists elsewhere. Most fled to Canada and helped settle that country, particularly Ontario and Nova Scotia.
Guide to Finding a Loyalist Ancestor in Upper Canada (Ontario) is available in paperback or as an e-book on Amazon.com and on Amazon.ca
Other Loyalist genealogy records you will want to consult are Loyalist Muster Rolls
for Butler's Rangers;
Sir John Johnston's [Johnstone's] Brigade; King's Royal Regiment of
New York (KRRNY); Men From the Turloch Militia who Joined KRRNY or
Butler's Rangers; 1778 List of Men From Pennsylvania who joined the
British Army & British Regiments who served in North America during
the French and Indian Wars.
To find Loyalist ancestors, start with Loyalist History. This will help you understand what a Loyalist was, who they were, what Military Loyalist Regiments for British and Loyalist troops during the American Revolution, and where they settled. Butler's Rangers, mustered by Col. John Butler in New York and consisting of Mohawk Indians and men from New York is one of the Regiments featured.
You can also read about other Loyalist families:
Isaac Van Valkenburg aka Vollick Loyalist from New York with Butler's Rangers in Niagara
Jonas Larroway Loyalist from New York with Butler's Rangers in Niagara
Shainholdts- A Loyalist in Butler's Rangers
Elisha Wilcox (Willcox, Willcocks) Sr
Loyalist from New England with Butler's Rangers in Niagara, and his
children Asa Wilcox, Hezekiah Wilcox, Elisha Wilcox Jr, Sarah Wilcox
Emmons, James Wilcox, also his son's father in law Gasper Brown