The other two answers define cross-cutting cleavages and provided American examples, so I thought I'd contribute a global case.
In India, the north-south divide splits people economically. Southern Indian states are more developed and possess higher quality of life. The Indian tech sector is concentrated in its southern states, which also have sole access to its coastline and port cities. This means that North Indians tend to have very different political and economic needs than their southern countrymen.
India has also faced a long struggle with the legacy of its caste system. Ancient Indian society strictly enforced its castes; modern society still carries the lingering toxicity of those old prejudices. India's first Dalit (lowest cast) president was elected in 1997, and the second made news when he was elected earlier this year.
But fortunately for the Indian state, castes are not geographically distributed. Dalits and Brahmins live side-by-side in northern, southern, eastern, and western Indian states. This means that an Indian politician must reach across caste lines to appeal to northern or southern voters, and they must connect with people from all regions if they want to build a voting bloc associated with a given caste.