The main difference between County and Province is that the County is a geographical and administrative region in some countries and Province is a territorial entity within a country or state.
A county is a geographical region of a country used for administrative or other purposes, in certain modern nations. The term is derived from the Old French conté or cunté denoting a jurisdiction under the sovereignty of a count (earl) or a viscount. The modern French is comté, and its equivalents in other languages are contea, contado, comtat, condado, Grafschaft, graafschap, Gau, etc. (cf. conte, comte, conde, Graf). When the Normans conquered England, they brought the term with them. The Saxons had already established the districts that became the historic counties of England, calling them shires (many county names derive from the name of the county town (county seat) with the word "shire" added on: for example, Gloucestershire and Worcestershire). The Anglo-Saxon's "earl" and "earldom" were taken as equivalent to the continental use of "count" and "county" under the conquering Normans, and over time the two blended and became equivalent terms. Further, the later-imported term became a synonym for the native English word scir ([ʃiːr]) or, in Modern English, shire. Since a shire was an administrative division of the kingdom, the term "county" evolved to designate an administrative division of states (federal states like those of Germany and the United States) or of a national government in most other modern uses. In the United States and Canada, founded 600 years later on the British traditions, counties are usually an administrative division set by convenient geographical demarcations, which in governance have certain officeholders (e.g. Sheriffs and their departments) as a part of the state/province mechanisms, including geographically common court systems. A county may be further subdivided into districts, hundreds, townships or other administrative jurisdictions within the county. A county usually, but not always, contains cities, towns, townships, villages, or other municipal corporations, which in most cases are somewhat subordinate, or dependent upon county governments. Depending on the nation and the municipality and local geography, municipalities may or may not be subject to direct or indirect county control—the functions of both levels are often consolidated into a city government when the area is densely populated. Outside English-speaking countries, an equivalent of the term "county" is often used to describe sub-national jurisdictions that are structurally equivalent to counties in the relationship they have with their national government; but which may not be administratively equivalent to counties in predominantly English-speaking countries.
A province is almost always an administrative division, within a country or state. The term derives from the ancient Roman provincia, which was the major territorial and administrative unit of the Roman Empire's territorial possessions outside Italy. The term province has since been adopted by many countries, and in those with no actual provinces, it has come to mean "outside the capital city". While some provinces were produced artificially by colonial powers, others were formed around local groups with their own ethnic identities. Many have their own powers independent of federal authority, especially in Canada. In other countries, like China, provinces are the creation of central government, with very little autonomy.
From Middle English countee, counte, conte, from Anglo-Norman counté, Old French conté (French comté), from Latin comitātus (“jurisdiction of a count”), from comes (“count, earl”). Doublet of comitatus, borrowed directly from Latin.
county (plural counties)
county (comparative more county, superlative most county)
Middle English provynce, from Anglo-Norman province, Middle French province, from Latin prōvincia (“territory brought under Roman domination; official duty, office, charge, province”), from Proto-Indo-European *prōw- (“right judge, master”). Cognate with Gothic 𐍆𐍂𐌰𐌿𐌾𐌰 (frauja, “lord, master”), Old English frēa (“ruler, lord, king, master”). See also frow.
province (plural provinces)
"Province" is the generic English term for such primary divisions of a country, but is not used where another official term has widespread use, such as France's regions and departments or America's states. "Territories" and "colonies" are sometimes distinguished from provinces as unorganized areas of low or foreign population, which are not considered an integral part of the country. Sovereign subdivisions of a larger whole, such as the principalities of the former Holy Roman Empire or the countries with the European Union, are likewise not usually described as provinces.