As the third highest of harvested area for maize among regencies in North Sumatera Province, Simalungun Regency shares significant contribution for the total production. Unfortunately, there is a declining trend of production for five years influencing by total harvested area and productivity. These two factors are the justification to conduct this study with the aims to identify the potency of land resource for maize by measuring land-limitation factors and to introduce new varieties. Soil physic and chemical data were collected from field survey and laboratory analysis, and GIS and Evaluation System for Land Suitability tools were operated to detect the land potency. Meanwhile, Random Block Design with three replications performed to determine the well-adapted varieties. The results show that Simalungun Regency has 165,311 ha of high potency of land for maize and 238,834 ha and 26,952 ha has low and no potency of land, respectively. Nutrient retention and erosion hazard are the predominant limitation factors. Especially for adaptive-variety testing, this study found that Srikandi Kuning provides the highest productivity, 7.79 t/ha, that insignificantly difference with Bisma, Gumarang, Arjuna and Sukmaraga by 7.44, 7.27, 7.06 and 6.89 t/ha respectively. Conversely, Krisna has the lowest productivity, 4.98 t/ha, which is lower than provincial level. Applying land conservation measures and adopting new/tolerant variety be able to support sustainable maize production.