From Wikipedia (via Google):-
In an English village since the 17th century and possibly to this day, the squire was the person of pre-eminent social position in the community by virtue of being the principal landowner. Squires were gentleman with a coat of arms and were often related to peers. Many could claim descent from knights and had been settled in their estates for hundreds of years. The squire more often than not lived at the village manor house, and owned an estate in or comprising the village with the villagers being his tenants. If the squire owned the living (was patron) of the parish church—and he often was— he would choose the rector which role might often be filled by a younger son of the squire. Some squires also became the local rector themselves and were known as squarsons - a combination of the words squire and parson. The squire would also have performed a number of important local duties in particular that of justice of the peace or MP. Politically, during the 19th century squires tended to be conservative or tory whereas the greatest landlords tended to be liberals.
The position of squire was traditionally associated with occupation of the manor house which would often itself confer the dignity of squire. Acceptance is today more likely to be dependent upon a recognition of good manners, lineage and long family association than upon acreage, which, while relevant, is nowadays likely to be considerably smaller than in former years due to high post-war death duties and the prohibitive costs associated with maintaining large country houses which forced many squires to break up and sell their estates. The position is today less recognised but in many communities, where the family remains in occupation of the manor house, the tradition continues.
The term Squire comes from Esquire, a title of gentility immediately above that of Gentleman and can be conferred by the Crown (through the College of Arms), or through certain appointments (e.g. legal or military) or through family descent (the helmet displayed on a coat of arms distinguishes Esquire from Gentleman). The title is placed at the end of the name, abbreviated to Esq., and is used in placed of the style for a Gentleman, that of "Mr". Traditionally, it was a senior title to that of "Mr" but this distinction, though technically extant, is often overlooked today and both titles are often used indiscriminately.