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Chromosome numbers are reported here for the first time from 117 individuals of <i>Solidago rugosa</i> and <i>S. fistulosa</i>. Including 178 previously published reports for the two species plus <i>S. latissimifolia</i>, chromosome numbers have been determined from 295 individuals from 269 locations. Only diploids (2<i>n</i> = 18) were found throughout the range of <i>S. fistulosa</i> on the coastal plain in the eastern U.S.A. (44 counts). Diploids (2<i>n</i> = 18) were found in the northern portion of the range of <i>S. latissimifolia</i>, and tetraploids (2<i>n</i> = 36) and hexaploids (2<i>n</i> = 54) were found in the central and southern portions of the range (nine counts in total). Diploids (2<i>n</i> = 18) were found throughout the range of <i>S. rugosa</i> in much of eastern North America in four of the five varieties (northern var. <i>rugosa</i>, var. <i>sphagnophila</i>; southern var. <i>aspera</i> and var. <i>celtidifolia</i>). Tetraploids (2<i>n</i> = 36) were found in all four of these varieties and exclusively in var. <i>cronquistiana</i> in the southern high Appalachian Mountains. Hexaploids (2<i>n</i> = 54) were found in var. <i>sphagnophila</i> at scattered locations. One possible hexaploid in var. <i>rugosa</i> was found in the Allegheny Mountains. The diversity in ploidy levels was independent of the size of the range and the diversity of growing conditions among the three species of <i>S.</i> subsect. <i>Venosae</i>.