New leads need be routed to the correct Sales person based on the lead address.

Validation Rules prevent records from being saved when data does not meet defined criteria; they do not assign or route records to users.

Lead Assignment Rules evaluate conditions on incoming leads - including address fields like state, country, or postal code - and assign ownership to the appropriate user or queue based on matching criteria.

Formula Fields calculate and display a value on a record but cannot assign record ownership or trigger any routing logic.

Escalation Rules apply to Cases in Service Cloud, not to Leads, and are used to escalate unresolved cases rather than route new records.