The main online reference for human mtDNA phylogeny is PhyloTree, however it has little information on relevant surveys or much less on where each haplogroup is found. This page and subpages will try to address all those aspects.
The basic structure of human matrilineal phyologeny, which is concentrated in Africa for the first many levels, follows. The root is sometimes known as mitochondrial Eve, on Hebrew mythological imaginery.
These two last L3 sublineages, M and N, make up most of the the non-African ancestry.
The names of most lineages are reflective of the sequence of their discovery and description rather than any logic. Initially all lineages of Africa were described L (as not N or M), but later a host of fundamental diversity was found to exist in this continent.