The 2015 Informatics Needs and Capacity of Local Health Departments (LHDs) survey is the most recent comprehensive source of quantitative data on LHD informatics. Conducted by the National Association of County & City Health Officials (NACCHO), this is the third nationally representative quantitative study of LHD informatics since 2009. The previous 2 comprehensive quantitative assessments were conducted by NACCHO in 2009-2010 and 2011. Given that public health informatics is rapidly evolving, the 2015 Informatics survey is a much-needed country-wide assessment of the current informatics needs and capacities of LHDs. This article outlines detailed methodology used in the 2015 Informatics survey, including instrument development, pretesting, sampling design and sample size, survey administration, and sampling weights. A 9-member advisory committee representing federal, state, and local health agency representatives guided the design and implementation of this study. The survey instrument was organized into 6 topic areas: demographics, physical infrastructure, skills and capacity available, public health workforce development needs, electronic health records, and health information exchange. The instrument was pretested with a sample of 20 LHDs and subsequently pilot-tested with 30 LHDs. The survey was administered via the Qualtrics survey software to the sample of 650 LHDs, selected using stratified random sampling. The survey was fielded for approximately 8 weeks and 324 usable responses were received, constituting a response rate of 50%. Statistical weights were developed to account for 3 factors: (a) disproportionate response rate by population size (using 7 population strata), (b) oversampling of LHDs with larger population sizes, and (c) sampling rather than a census approach.