re: Forgotten Graves

To be fair, the graves were likely there before the interstate highway.

One can always reckon a city's growth patterns by the locations of the cemeteries. We can chronicle the physical growth of New Orleans this way: the location of St. Peter Cemetery is known.
St. Louis #1
St. Louis #2
St. Louis #3/St. Patricks (all of them) Cypress Grove/ Odd Fellow's Rest/Metairie/Greenwood/Holt.
Going out to Gentilly: Mount Olivet/Hebrew's Rest
The current "Potter's Field" is now way out along Chef Highway, as I recall.

Heading uptown:
Lafayette
Valence Street
St. Joseph and Carrollton

East Jefferson only has Garden of Memories and Providence Park. Both of those were once on the edge of "new" neighborhoods.

You see the same pattern on the West Bank. For Algiers there are St. Mary's and St. Bartholomew that were once at the very edge of Algiers, bordering on John McDonogh's plantation. On his land, again once at the edge of civilization is McDonoghville Cemetery (my paternal grandparents, her siblings, are there)

In Gretna, Hook and Ladder was built when Gretna was much smaller (maternal grandparents and most of their siblings and kids, as well as my father) a couple blocks behind St. Joseph. The black Baptist cemetery is a block away and borders the Expressway, which was built over part of it.

Further down La. 23 toward the back edge of Gretna, at one time, is Westlawn. Now it's more-or-less the back of Terrytown.

So on and so on.