This article highlights the use of bacterial artificial chromosome (BAC) constructs to target Cre recombinase expression to specific neuron populations in the brain. The authors constructed 10 BAC-Cre constructs for genes expressed in specific neurotransmitter systems, forebrain circuits, and neuron types. These constructs produced 14 transgenic mouse lines with Cre expression in specific neuronal and glial populations. The study demonstrates the general applicability of BAC-Cre constructs for efficient production of Cre drivers targeting specific cell populations, extending the Gene Expression Nervous System Atlas (GENSAT) project. The article also discusses variations in Cre expression patterns, including ectopic and partial expression, and emphasizes the importance of characterizing these patterns for specific experimental applications. The 14 new BAC-Cre driver lines will be added to the GENSAT resource, providing valuable tools for neuroscience research.This article highlights the use of bacterial artificial chromosome (BAC) constructs to target Cre recombinase expression to specific neuron populations in the brain. The authors constructed 10 BAC-Cre constructs for genes expressed in specific neurotransmitter systems, forebrain circuits, and neuron types. These constructs produced 14 transgenic mouse lines with Cre expression in specific neuronal and glial populations. The study demonstrates the general applicability of BAC-Cre constructs for efficient production of Cre drivers targeting specific cell populations, extending the Gene Expression Nervous System Atlas (GENSAT) project. The article also discusses variations in Cre expression patterns, including ectopic and partial expression, and emphasizes the importance of characterizing these patterns for specific experimental applications. The 14 new BAC-Cre driver lines will be added to the GENSAT resource, providing valuable tools for neuroscience research.