4000 may refer to:

• 4000 (number)
• 4000 series of integrated circuits
• Meitetsu 4000 series or Odakyu 4000 series train types
• Weather Star 4000 a computer system used to display local forecasts on The Weather Channel
• The last year of the 4th millennium, a leap year starting on Saturday

• Vermont Railway System
• Vermont Representative districts, 2002–2012
• Vermont Representative Districts, 2002–2012
• Vermont Republican primary, 2012
• Vermont Route 100A
• Vermont Route 100B
• Vermont Route 101
• Vermont Route 104
• Vermont Route 104A
• Vermont Route 105A
• Vermont Route 106
• Vermont Route 109
• Vermont Route 110
• Vermont Route 111
• Vermont Route 117
• Vermont Route 118
• Vermont Route 120
• Vermont Route 121
• Vermont Route 122
• Vermont Route 139
• Vermont Route 140
• Vermont Route 141
• Vermont Route 147
• Vermont Route 214
• Vermont Route 232