In much of Eastern Africa, the last decade has seen a renewed interest in spatial development plans that link mineral exploitation, transport infrastructure and agricultural commercialisation. While these development corridors have yielded complex results – even in cases where significant investments are yet to happen – much of the existing analysis continues to focus on economic and implementation questions, where failures are attributed to inappropriate incentives or lack of ‘political will’. Taking a different – political economy – approach, this article examines what actually happens when corridors ‘hit the ground’, with a specific interest to the diverse agricultural commercialisation pathways that they induce. Specifically, the article introduces and analyses four corridors – LAPSSET in Kenya, Beira and Nacala in Mozambique, and SAGCOT in Tanzania – which are generating ‘demonstration fields’, economies of anticipation and fields of political contestations respectively, and as a result, creating – or promising to create – diverse pathways for agricultural commercialisation, accumulation and differentiation. In sum, the article shows how top-down grand-modernist plans are shaped by local dynamics, in a process that results in the transformation of corridors, from exclusivist ‘tunnel’ visions, to more networked corridors embedded in local economies, and shaped by the realities of rural Eastern Africa.