The Midlands is the name for the central part of England. People almost always say the Midlands, with the and with a capital M. It is not one city; it is a group of counties in the middle of the country, and Birmingham is the biggest city. People often split it into the West Midlands and the East Midlands. The border is not a fence on the ground; it is a region people recognise, the way they talk about “the North” or “the South”. Though actually, in Ireland people also say the Midlands for the middle of Ireland, so if the conversation is not about England, check which country they mean. For the English-learner sense, it is central England.