This article presents approaches to spectral interference management and mitigation in integrated circuits and systems. In dense environments where multiple devices communicate simultaneously in the same spectrum without coordination or resource allocation, reliable communication and network performance is challenging. Approaches to out-of-band (OOB) blockers and harmonic blockers using IC N-path structures and various architectures are developed. Techniques for OOB blockers emphasize synthesizing high-order frequency filtering directly at the antenna, including creating high-order networks across the low noise (transconductance) amplifier (LN(T)A), and translating high-order baseband (BB) low-pass filtering to RF. Harmonic blockers emphasize harmonic rejection (HR) approaches to maximize receiver dynamic range (DR) that include earlier stage HR designs, passive HR structures, and minimized switching in the down-conversion path.