| 5 | Greggs | Other catering premises | Three Rivers | WD19 7DT |
| 5 | Greggs @ Esso Service Station | Other catering premises | Three Rivers | WD4 8HR |
| 5 | Greggs PLC | Other catering premises | Three Rivers | WD3 1AP |
| 5 | Grocer On The Green | Retailers - other | Three Rivers | WD3 3LE |
| 5 | Grove Cocktail Co | Mobile caterer | Three Rivers | WD5 |
| 5 | HCL @ Abbots Langley Primary School | School/college/university | Three Rivers | WD5 0BQ |
| 5 | HCL @ Arnett Hills JMI School | School/college/university | Three Rivers | WD3 4BT |
| 5 | HCL @ Breakspeare School | School/college/university | Three Rivers | WD5 0BU |
| 5 | HCL @ Colnbrook Special School | School/college/university | Three Rivers | WD19 7UY |
| 5 | HCL @ Eastbury Farm JMI School | School/college/university | Three Rivers | HA6 3DG |
| 5 | HCL @ Garston Manor School | School/college/university | Three Rivers | WD25 7HR |
| 5 | HCL @ Greenfield JMI School | School/college/university | Three Rivers | WD19 6QH |
| 5 | HCL @ Little Green JMI School | School/college/university | Three Rivers | WD3 3NJ |
| 5 | HCL @ Malvern Way School & Nursery | School/college/university | Three Rivers | WD3 3QQ |
| 5 | HCL @ Maple Cross Junior School | School/college/university | Three Rivers | WD3 9SS |
| 5 | HCL @ Rickmansworth Park JMI School | School/college/university | Three Rivers | WD3 1HU |
| 5 | HCL @ Shepherd Primary School | School/college/university | Three Rivers | WD3 8JJ |
| 5 | HCL @ St Catherine Of Siena RC School | School/college/university | Three Rivers | WD25 7HP |
| 5 | HCL @ St Joseph's RC JMI School | School/college/university | Three Rivers | WD19 7DW |
| 5 | HCL @ St Mary's C Of E Primary School | School/college/university | Three Rivers | WD3 1NY |
| 5 | HCL @ St Meryl School | School/college/university | Three Rivers | WD19 5BT |
| 4 | HCL @ St Peter's School | School/college/university | Three Rivers | WD3 8HD |
| 5 | HCL @ Woodhall Primary & Nursery School | School/college/university | Three Rivers | WD19 6QX |
| 5 | HCL @ Yorke Mead Primary School | School/college/university | Three Rivers | WD3 3PX |
| 5 | Hannah's Kitchen | Retailers - other | Three Rivers | WD3 |
| 5 | Hanola Bakery | Other catering premises | Three Rivers | WD3 |
| 5 | Harvester | Pub/bar/nightclub | Three Rivers | WD3 3RX |
| 4 | Hemel Newsagent | Retailers - other | Three Rivers | WD19 7NT |
| 5 | Henderson Hub - Elviras | Restaurant/Cafe/Canteen | Three Rivers | WD5 0AR |
| 4 | High Elms Manor | Restaurant/Cafe/Canteen | Three Rivers | WD25 0JX |
| 5 | Hillside Pre-School | Hospitals/Childcare/Caring Premises | Three Rivers | WD3 5AS |
| Awaiting | Hima's Flavoured Peanuts | Retailers - other | Three Rivers | WD5 |
| 5 | Holland & Barrett | Retailers - other | Three Rivers | WD3 1AN |
| 5 | Hollands | Retailers - other | Three Rivers | WD3 1EE |
| 4 | Holloways Super Store Ltd | Retailers - other | Three Rivers | WD19 7NT |
| 5 | Home Caterer - Mrs J Gadher | Other catering premises | Three Rivers | WD25 |
| 5 | Hug A Leaf | Retailers - other | Three Rivers | WD3 6BX |
| 5 | Hunton Park Hotel | Hotel/bed & breakfast/guest house | Three Rivers | WD4 8PN |
| 5 | Hunton Spice | Takeaway/sandwich shop | Three Rivers | WD4 8RD |
| 5 | IFG@St Michael's Catholic High | School/college/university | Three Rivers | WD25 0SS |
| 5 | Iceland | Retailers - supermarkets/hypermarkets | Three Rivers | WD3 1AJ |
| 5 | Ilze's Chocolat | Other catering premises | Three Rivers | HA6 |
| 5 | Impact Food Group @ York House School | School/college/university | Three Rivers | WD3 4LW |
| Awaiting | Impact Food Group Trading As Dolce @Sarratt C Of E Primary S | School/college/university | Three Rivers | WD3 6AS |
| Awaiting | Imperial & Grill | Restaurant/Cafe/Canteen | Three Rivers | WD5 0LA |
| 5 | In The Mood For Food | Mobile caterer | Three Rivers | WD3 |
| 5 | India Rasoi | Restaurant/Cafe/Canteen | Three Rivers | WD3 5RB |
| 4 | Iuliana Tudorache | Retailers - other | Three Rivers | WD19 |
| 5 | J Cakes | Retailers - other | Three Rivers | WD3 |
| 5 | Jabula | Other catering premises | Three Rivers | HA6 |