* ''Geranium aculeolatum''
* ''Geranium aequale''
* ''Geranium aequatoriale''
* ''Geranium affine''
* ''Geranium albanum''
* ''Geranium albicans''
* ''Geranium albidum''
* ''Geranium albiflorum''
* ''Geranium album''
* ''Geranium alonsoi''
* ''Geranium alpicola''
* ''Geranium amatolicum''
* ''Geranium amoenum''
* ''Geranium andicola''
* ''Geranium andringitense''
* ''Geranium angelense''
* ''Geranium angustipetalum''
* ''Geranium antisanae''
* ''Geranium antrorsum''
* ''Geranium apricum''
* ''Geranium arabicum''
* ''Geranium arachnoideum''
* ''Geranium arboreum'' – Hawaiʻi Red Cranesbill, Hawaiian Red-flowered Geranium
* ''Geranium ardjunense''
* ''Geranium argenteum'' – Silvery Cranesbill
* ''Geranium argentinum''
* ''Geranium aristatum''
* ''Geranium asiaticum''
* ''Geranium asphodeloides'' – Turkish Rock Geranium
* ''Geranium atlanticum''
* ''Geranium atropurpureum'' – Western Purple Cranesbill
* ''Geranium austroapenninum''
* ''Geranium ayacuchense''
* ''Geranium ayavacense''
* ''Geranium azorelloides''