Slavery
Most of the characters featured in River Sing Me Home are slaves. They have been in bondage for most, if not all, of their lives and knowing nothing but slavery. The novel's main character, named Rachel, was born into slavery. Shortly after their births, her children were taken from her at a very young age that they too could be sold into slavery. Slavery has destroyed Rachel and other enslaved people in many ways; slavery has brought nothing to enslaved people but pain and suffering. And slavery, River Sing Me Home argues and shows, is one of the worst institutions ever perpetrated against people of color.
Connection
At the end of the day, human beings desire and need connection in their lives. Specifically, they need friends and family to color their lives and make it better. Because of the institution of slavery, connection has been stripped from slaves. In many cases, they lose access to their kids and their spouses too. Invariably, they also lose access to the world at large. As a slave, they don't have the ability to connect with their friends, family, and the world at large. In other words, they lose access to their friends and family, two things which make humans human.
Family
Family plays an understated, but still significant role in Rachel's life and the lives of the characters in the novel. For many slaves, family is something they can only aspire to. Some slave masters don't allow their slaves to have sex and thus get pregnant. Others allow their slaves to have children, but sell them into slavery somewhere far away. Few allow the slave's children to stay with their mother and far. These traumatic experiences lead many to yearn for family (either children or a spouse, which many slavers wouldn't let their slaves have).