A nonplanar graph is a graph that is not planar. The numbers of simple nonplanar graphs on n = 1, 2, ... nodes are 0, 0, 0, 0, 1, 14, 222, 5380, 194815, ... (OEIS A145269), with the corresponding number of simple nonplanar connected graphs being 0, 0, 0, 0, 1, 13, 207, 5143, 189195, ... (OEIS A145270). The following table summarizes some named nonplanar graphs.

critical nonplanar graph | cubic nonplanar graph | Kuratowski's theorem | planar graph