Generally, "region" refers to a geographic area, whereas "district" usually refers to a political or organizational area. For instance, 2009's fantastic Sci-Fi hit "District 9" referred to a portion of Johannesburg that the government allows aliens to live in. The title of the film isn't "Region 9" because this place isn't simply a part of the map that has more aliens than any other, it is a ghetto that was created by the government.

In the U.S.: There are not standardized definitions of these words, but "region" is more general and used for large geographic areas, like a country or state, and "district" is more specific, and used more frequently to describe areas within a city. "District" can also be a formally defined or officially designated entity -- for example, "school district," "Congessional district," "City Council district," etc.

So, for example, in Ukrane there are 24 regions. Every region has its capital city. For example, Im living in Kharkiv, but in Kharkiv`s region there are few cities and countysides, that are not that big. Its more than 1,5 million citizens in Kharkiv, but about 2 millions in Kharkiv`s region. District is like a region but in the city. Kharkiv is separated on 9 districts, each having its own control center. This type of policy is spread only on post soviet space (suck countries as Ukraine, Russian, Belarus). Anyway, hope it was useful for you)

Hey Mona,  a district is a part of a town or city.  A region is a much larger area referring to areas of a country or part of the world.