The Quantified Community (QC)—a long-term neighborhood informatics research initiative—is a network of instrumented urban neighborhoods that collect, measure, and analyze data on physical and environmental conditions and human behavior to provide a rich resource to better understand how neighborhoods and the built environment affect individual and social well-being. To advance this work, my team has developed the QC Urban Sensor Array—a low-cost but highly accurate sensor array to measure and track localized environmental conditions, down to the individual street, block, or building. The devices measure air quality, noise, light levels, pedestrian counts, and temperature/pressure/humidity. We then combine sensor data with administrative, mobility, social media, and Wi-Fi usage data to create a neighborhood profile to track changes over time and compare to other areas of the city. These data will help communities identify and solve problems, focusing on issues of environmental health and activity, through new data and data visualization and a deeper understanding of neighborhood activity and ecology. We have partnered with the Red Hook Initiative (RHI), a local social services community organization, to install the sensors and engage with the local community to provide additional, volunteered data. We also work closely with the NYC Mayor’s Office of Technology and Innovation and the NYC Economic Development Corporation to coordinate our activities. Data transparency and accessibility are paramount to this research.