Synchronization of oscillators based on anharmonic nanoelectromechanical resonators. Experimental implimentation allows for unprecedented observation and control of parameters governing the dynamics of synchronization. Close quantitative agreement is found between experimental data and theory describing reactively coupled Duffing resonators with fully saturated feedback gain. In the synchonized state, a significant reduction in the phase noise of the oscillators is demonstrated, which is key for applications such as sensors and clocks. Oscillator networks constructed from nanomechanical resonators form an important laboratory to commercialize and study synchronization-given their high-quality factors, small footprint, and ease of co-integration with modern electronic signal processing technologies. Networks can be made including one-, two-, and three-dimensional networks. Triangular and square lattices can be made.