This paper presents a new dataset on subnational ethnolinguistic and religious diversity in Sub-Saharan Africa covering 36 countries and almost 400 first-level administrative units. We use population censuses and large-scale household surveys to compile detailed data on the ethnolinguistic composition of each region and match all reported ethnicities to Ethnologue, a comprehensive catalog of world languages. This matching allows us to standardize the notion of an ethnolinguistic group and account for relatedness between language pairs, a correlate of shared history and culture, when calculating diversity indices. Exploiting within-country variation provided by our new dataset, we find that local public goods provision, as reflected in metrics of education, health, and electricity access, is negatively related to ethnolinguistic diversity, but only if the underlying basic languages are first aggregated into larger families or if linguistic distances between groups are taken into consideration. In other words, only deeprooted diversity, based on cleavages formed in the distant past, is strongly inversely associated with a range of regional development indicators. Furthermore, we show that subnational diversity has been remarkably persistent over the past two-three decades implying that population sorting in the short to medium run is unlikely to bias our main findings.