The recent expansion of cotton acreage in the Northern High Plains of Texas has raised concerns about the occurrence of a diverse Fusarium community, particularly Fusarium oxysporum f. sp. vasinfectum race 4, which is favored by cool early-season temperatures that often occur in the region. This study investigated the diversity, distribution, and pathogenicity of Fusarium species associated with cotton and corn fields across 10 counties in the Northern High Plains. A total of nine Fusarium species were isolated: F. incarnatum, F. equiseti, F. solani, F. verticillioides, F. proliferatum, F. clavum, F. oxysporum, F. flocciferum, and one unidentified Fusarium sp. The highest species diversity was observed in Sherman County. Fusarium solani was the most frequently isolated species (39%) across all counties, followed by F. equiseti (22%), while F. flocciferum was the least frequent (2%). Pathogenicity assays conducted under greenhouse conditions showed that F. incarnatum caused significantly higher disease severity on aerial parts of cotton, while F. flocciferum and F. proliferatum caused significantly higher disease severity on roots. On corn, F. proliferatum caused significantly higher disease severity. Fusarium isolates were recovered from both symptomatic and asymptomatic roots following pathogenicity trials, suggesting endophytic colonization. This study revealed a complex Fusarium community capable of cross-infecting cotton and corn, with implications for regional disease management. The absence of Fusarium oxysporum f. sp. vasinfectum race 4 indicates that it may not yet have been introduced into the Northern High Plains; however, continued surveillance is warranted given its detection in New Mexico and adjacent counties in Texas.