Metropolitan fragmentation is considered the root cause of inequality among local governments. Self-governing localities have the power to exercise zoning and land-use laws to lock up their resources, which gives them a competitive edge against their neighbors. Localities are unique in terms of their economic capacity, fiscal strength, geographic location, racial makeup of their residents and their income status. Such differences reflect into variation in preference for urban infrastructure and the capacity of local governments to provide preferred services at the lowest possible taxes and fees. Some scholars have suggested consolidating localities into large regional governments to overcome such inequalities. However, studies focused on consolidated regional governments show that they have not been successful in fulfilling their promises. This manuscript is predicated on the argument that production of urban services need not be competitive as its provision, and localities can reap benefits of scale-economy and standardization of services through voluntary mutual cooperation and policy coordination without having to abdicate their rights of self-governance. The purpose of this manuscript vi is to identify various economic, political, social, and geographic characteristics of localities that influence the extent of cooperation among them. This manuscript intends to do that by using aggregate data and quantitative methods designed to overcome weaknesses faced by previous studies. The data used for this analysis comes from 1,164 general purpose local governments - cities, municipalities, counties, and townships - within 51 largest metropolitan statistical areas in the United States. It uses robust linear regression to identify causal relationship between variables representing local economic, social, political, and geographic characteristics and the extent of interlocal cooperation among localities. Metropolitan fragmentation, growth in the developmental sector, fiscal stress, poverty, and the senior population are found to positively influence local governments' decision to cooperate with their neighbors. Conversely, property value, growth in manufacturing sector, higher percentage of whites and the rich are found to negatively influence cooperation decisions. Similarly, localities in close proximity are found to engage less in interlocal cooperation, whereas African-American population is found to have no substantial influence on cooperation decisions. Besides, cities and municipalities are found to engage more in interlocal cooperation than counties, and localities in the South are found to be less inclined to pursue interlocal cooperation than the rest of the country.