Laser-cooled neutral atoms are capable of reaching extraordinary sensitivity and accuracy in the measurement of motion and fields. I will describe ongoing efforts to employ cold atomic ensembles for sensing at both large and small length scales. First, I will describe the development of atom interferometer inertial sensors in a commercial research setting, discuss techniques used to reach sensitivity levels of interest for navigation and Earth science applications, and review the challenges presented by applications requiring compact size, high dynamics, and operation in real-world environments. Second, at the Naval Research Laboratory, efforts are underway to address these challenges, including the degradation of sensor performance by near-resonant scattered light in compact atom interferometers. Finally, I will describe a new program aimed at trapping atoms adjacent to fabricated, chip-based nanophotonic optical waveguides for sensing and quantum network applications.