This work reviewed 103 studies of CH4 emissions from cities in the U.S. and Canada to consolidate the current state of knowledge and highlight key research priorities. The review found that estimates of citylevel CH4 emissions derived from TD measurements were dominantly larger than estimates from BU inventories. The extent of the discrepancy varied regionally, which is likely related to regional-based differences between cities in the age and material type of natural gas distribution infrastructure and overall importance of emissions from natural gas sources to city-level CH4 emissions. The largest discrepancies were generally reported in satellite-based TD studies, suggesting that the extent of the discrepancy may be sensitive to the measurement method. As noted by for upstream O&G methane emissions, TD > BU is not an issue unique to the urban space, but likely indicates that existing BU approaches are not capturing all the sources in cities and that the emissions and activity factors are not representative. Therefore, a refocusing of research to improve BU approaches to emissions estimation is warranted. Targeted measurements to expand source coverage and reduce assumptions, new and accessible datasets for researchers, and development of new urban-specific modeling approaches are required. Priority should be given to natural gas sources given that the studies showed the largest discrepancies between TD and BU estimates for this source category and their importance to total CH4 emissions in most U.S. and Canadian cities.