The 33-year-old was a free agent after leaving Leyton Orient at the end of last season.
Scunthorpe have now signed 10 new players this summer.
Henderson scored eight goals in 25 appearances for Orient last term following a move from Nottingham Forest.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Chorley | 17 | 9 | 5 | 3 | 28 | 19 | 9 | 32 |
| 2 | Kidderminster HarriersKidderminster | 17 | 9 | 4 | 4 | 26 | 12 | 14 | 31 |
| 3 | Curzon AshtonCurzon Ashton | 16 | 9 | 3 | 4 | 21 | 11 | 10 | 30 |
| 4 | Scunthorpe UnitedScunthorpe | 17 | 8 | 5 | 4 | 31 | 14 | 17 | 29 |
| 5 | Buxton | 18 | 9 | 1 | 8 | 29 | 21 | 8 | 28 |
| 6 | Hereford UnitedHereford | 17 | 7 | 6 | 4 | 25 | 17 | 8 | 27 |
| 7 | Brackley Town | 16 | 8 | 3 | 5 | 19 | 13 | 6 | 27 |
| 8 | King's Lynn TownKing's Lynn | 17 | 8 | 3 | 6 | 20 | 19 | 1 | 27 |
| 9 | Alfreton TownAlfreton | 15 | 7 | 5 | 3 | 20 | 14 | 6 | 26 |
| 10 | Chester FCChester | 16 | 7 | 4 | 5 | 18 | 16 | 2 | 25 |
| 11 | SouthportSouthport | 17 | 7 | 4 | 6 | 25 | 29 | -4 | 25 |
| 12 | Spennymoor TownSpennymoor | 17 | 6 | 6 | 5 | 25 | 19 | 6 | 24 |
| 13 | Leamington FCLeamington | 16 | 6 | 5 | 5 | 22 | 16 | 6 | 23 |
| 14 | Darlington | 17 | 5 | 7 | 5 | 18 | 18 | 0 | 22 |
| 15 | South Shields | 17 | 7 | 1 | 9 | 19 | 27 | -8 | 22 |
| 16 | Peterborough SportsP'boro Sports | 17 | 6 | 3 | 8 | 18 | 23 | -5 | 21 |
| 17 | Scarborough AthleticScarborough Ath | 15 | 5 | 5 | 5 | 19 | 19 | 0 | 20 |
| 18 | Farsley CelticFarsley Celtic | 17 | 6 | 2 | 9 | 18 | 26 | -8 | 20 |
| 19 | Oxford CityOxford City | 16 | 4 | 6 | 6 | 23 | 29 | -6 | 18 |
| 20 | Warrington Town | 17 | 4 | 6 | 7 | 17 | 23 | -6 | 18 |
| 21 | RadcliffeRadcliffe | 17 | 4 | 5 | 8 | 21 | 30 | -9 | 17 |
| 22 | Marine AFC | 16 | 3 | 4 | 9 | 7 | 21 | -14 | 13 |
| 23 | Needham Market | 17 | 3 | 3 | 11 | 12 | 31 | -19 | 12 |
| 24 | Rushall Olympic | 16 | 3 | 2 | 11 | 16 | 30 | -14 | 11 |
| > National League North Full Table | |||||||||
