The two figures, one of each side of the granite slab, are reaching towards each other with their hands. The male figure represents the first slave brought to Portsmouth in bondage, and the female figure represents Mother Africa.
The African Burying Ground is located on Chestnut Street, between Court and State Streets in Portsmouth, New Hampshire. There is street parking with meters nearby on both Court and State. It is a short walk from Market Square. Although this is now downtown Portsmouth, remember that in the early 1700s this area was the outskirts of the settlement- the fringes of regular society.
Heather Wilkinson Rojo, "Our Juneteenth visit to Portsmouth's African Burial Ground", Nutfield Genealogy, posted June 25, 2015 (http://nutfieldgenealogy.blogspot.com/2015/06/our-juneteenth-visit-to-portsmouths.html : accessed [access date]).