This research aims at verifying location claims of Internet clients. A wide spectrum of location-sensitive Internet applications could benefit from verifying location assertions. To that end, we designed Client Presence Verification (CPV), a delay-based mechanism by which a location assertion could be verified to a certain degree of granularity. When a location is asserted, three verifiers measure round-trip and one-way delays between themselves and the client. The verifiers then corroborate, based on the measured delays, the client’s physical presence inside the triangle determined by their geographic locations.