Voltage: United States uses 110-120 volts AC, 60Hz frequency - different from most countries which use 220-240V.
Plug Types: Type A (two flat parallel pins) and Type B (two flat parallel pins + grounding pin) are standard. These are North American style plugs.
Adapters Needed: Visitors from Europe, Asia, Africa, Australia, and South America will need plug adapters. Purchase before traveling or at airports, electronics stores (Best Buy, Target), or pharmacies (CVS, Duane Reade). Expect to pay $10-20 for quality adapters.
Voltage Converters: If your devices only support 220-240V, you'll need a voltage converter/transformer (not just an adapter). However, most modern electronics (laptops, phone chargers, cameras) are dual-voltage (110-240V) - check device label. Only the plug adapter is needed for dual-voltage devices.
USB Charging: USB outlets increasingly common in hotels, cafes, and public spaces. USB charging cables work universally. Consider bringing a multi-port USB charger.
Power Banks: Useful for long days exploring. Ensure power banks are <100Wh for airline travel. Many cafes and museums offer charging stations.
Where to Buy: B&H Photo (Manhattan's largest electronics store), Apple Store (multiple locations), Best Buy, Target, or any pharmacy chain. Airport shops carry adapters but at premium prices.