Multiple sources place the sanctuary near the Kwanza River. One source specifies the church stands on the left bank of the Kwanza River (web_search: Church of Nossa Senhora da Conceição da Muxima - Wikipedia). Another source mentions the sanctuary is located on the banks of the majestic Kuanza River (web_search: Angola. Mama Muxima, The Mother of the Heart. – Comboni...).

Multiple sources confirm the church's connection to Portuguese colonizers, the 16th/17th century, and its role as a center related to the slave trade. Wikipedia notes the church was built in the 16th century (Wikipedia: Church of Nossa Senhora da Conceição da Muxima) and that the village was occupied by the Portuguese in 1589 and the fortress built in 1599 (Wikipedia: Muxima). Another source explicitly states the sanctuary was a place where Africans were baptized before being shipped as slaves (web_search: Our Lady of Conceição da Muxima - Luanda).

The evidence strongly supports the elements of the claim. Sources confirm that enslaved Africans were baptized by Portuguese priests (web_search: Primary Source: Alamandini's "Portuguese Priests Baptizing Africans"). Furthermore, the evidence details the forced movement of enslaved people from the region to Luanda and then to the Americas (web_search: 1619 to 1819: Tell Them We Fought Back...). The specific distance of 110km (70 miles) is mentioned in the context of the first Africans in Virginia, which is a related historical detail, but the core elements—baptism by priests, forced journey to Luanda, and transport to the Americas—are corroborated by multiple sources.