Electronic circuits, electronic packages, and methods of fabrication are provided. The electronic circuit includes a multilayer circuit board, and a tamper-respondent sensor embedded within the circuit board. The tamper-respondent sensor defines, at least in part, a secure volume associated with the multilayer circuit board. In certain implementations, the tamper-respondent sensor includes multiple tamper-respondent layers embedded within the circuit board including, for instance, one or more tamper-respondent frames and one or more tamper-respondent mat layers, with the tamper-respondent frame(s) being disposed, at least in part, above the tamper-respondent mat layer(s), which together define the secure volume where extending into the multilayer circuit board. In certain embodiments, one or more of the tamper-respondent layers are divided into multiple, separate tamper-respondent circuit zones, with the tamper-respondent layers, including the circuit zones, being electrically connected to monitor circuitry within the secure volume.