The distinctive Early Classic megalithic style of the northern Maya Lowlands did not exist in isolation, but rather shared a number of features with monumental architecture of the central Petén. One particularly striking example is the triadic platform grouping, found at Naranjal as well as Uaxactún and other early sites of the northern and southern lowlands. The temporal and geographic distribution of Maya triadic platform groupings are reviewed in conjunction with such shared architectural features as rounded corners. These comparisons support the early dating ofmegalithic architecture and help define the special characteristics of this northern lowland style.