The variability of conditions that characterize karst terrain presents unique regulatory issues for local governments in the USA. Under our federalist system of governance, states hold the lion’s share of authority to regulate. However, states have not generally regulated karst, leaving the local governments to address karst issues through land use regulation. The standard land use tools fail to properly address the variability of karst conditions, however. Properly regulating karst likely entails a case-by-case approach, frowned upon by the law. Local governments rely mainly on buffer areas, performance standards, and required geophysical investigations to regulate karst areas. While buffer areas form a familiar type of regulation that will be upheld by the courts, the tool fails to take into the reality of karst. Performance standards meet legal requirements and can properly conserve karst areas but are difficult to draft. While required geophysical investigations respect the science of karst and effectively provide protection, the tool will likely fail legal challenges. Non-regulatory approaches can complement regulations or replace regulations in some areas. Conservation easements, purchase of development rights programs, low impact development, and conservation subdivision design are major non-regulatory approaches to address karst concerns. All of these tools can be effectively employed in karst, but their voluntary nature limits the scope of implementation. By combining modified land use tools and non-regulatory approaches, local governments can better address karst issues, but new models will need to be created to fully address karst concerns. For the present, local governments can use overlay zones, conditional use permits, and performance standards to address karst concerns. Ideally, however, state governments must step in, utilizing their broad regulatory authority to protect karst resources. Puerto Rico’s statutory protections provide a good example for other states, but more resources are required to implement the provisions in Puerto Rico and across the country. Education of key stakeholders can build support for karst protection and encourage more resources for implementation.