Where does “Croghan” come from?

Croghan (English) comes from Irish cruachan, from Irish crua, from Middle Irish crúaide, from Old Irish -e, from Old Irish lán, from Proto-Celtic ɸlānos, from Proto-Indo-European pl̥h₁nós, from Proto-Indo-European pleh₁- — to fill.

Ancestry of “Croghan”, step by step

Step	Language	Word	Meaning
1	Irish	cruachan	verbal noun of cruaigh; hardening
2	Irish	crua	hard, firm; difficult; severe
3	Middle Irish	crúaide	—
4	Old Irish	-e	Forms concrete or abstract nouns from adjectives
5	Old Irish	lán	full
6	Proto-Celtic	ɸlānos	full
7	Proto-Indo-European	pl̥h₁nós	full
8	Proto-Indo-European	pleh₁-	to fill

Every word from Proto-Indo-European pleh₁- →Every word from Proto-Indo-European pl̥h₁nós →Every word from Old Irish -e →