In our last installment, we discussed the challenges presented in subdividing properties on L.I. Most of these challenges are related to the overlapping jurisdictions of the myriad of government entities that are required to review, approve, or be notified of any proposed land use action.  Subdivisions in Nassau County must be approved by the "planning authority having jurisdiction" in an area. This means the County Planning Commission for land outside of the cities and villages, and city and village planning boards for properties within their boundaries. There is a catch, which many developers, attorneys and municipalities often miss. If the property is within 300 ft. of a municipal boundary, the adjacent municipality's planning authority also has to approve the subdivision. The failure to obtain this approval can render the subdivision incomplete, a result that is often not discovered until the new lot is being sold, sometimes even after construction is completed. Most planning boards would perform a pro forma review of the collateral application and issue a letter of approval or waiver. As land development has become more controversial, adjacent jurisdictions have sought to expand their authority and impose a higher level of review. There is debate within the field over the reach and purview of this collateral jurisdiction. Recent experience demonstrates that local planning agencies will continue to seek to expand their jurisdiction, and it is likely that the courts will be required to step in to clearly define their roles. It is essential that experienced L.I. zoning counsel be consulted on all subdivision applications to ensure that all requirements and formalities are met. Kathleen Deegan Dickson is a partner at Forchelli, Curto, Crowe, Deegan, Schwartz, Mineo & Cohn, Mineola, N.Y.