To form National Highway 44 (NH 44), a total of 7 national highways were merged.

The national highways that were merged to form NH 44 are:

1. National Highway 7 (NH 7):
- NH 7 is one of the longest national highways in India, stretching from Varanasi in Uttar Pradesh to Kanyakumari in Tamil Nadu.
- It passes through major cities like Nagpur, Hyderabad, Bangalore, and Madurai.
- NH 7 covers a distance of approximately 2,369 kilometers.

2. National Highway 4 (NH 4):
- NH 4 is a major national highway that connects Mumbai in Maharashtra to Chennai in Tamil Nadu.
- It passes through cities like Pune, Satara, Belgaum, Hubli, Bangalore, and Vellore.
- NH 4 covers a distance of approximately 1,235 kilometers.

3. National Highway 46 (NH 46):
- NH 46 connects Krishnagiri in Tamil Nadu to Ranipet in Andhra Pradesh.
- It passes through cities like Dharmapuri and Vaniyambadi.
- NH 46 covers a distance of approximately 102 kilometers.

4. National Highway 48 (NH 48):
- NH 48 connects Delhi to Chennai, passing through major cities like Jaipur, Kota, Vadodara, Mumbai, and Bangalore.
- It covers a distance of approximately 2,278 kilometers.

5. National Highway 63 (NH 63):
- NH 63 connects Ankola in Karnataka to Gooty in Andhra Pradesh.
- It passes through cities like Hubli and Bellary.
- NH 63 covers a distance of approximately 439 kilometers.

6. National Highway 206 (NH 206):
- NH 206 connects Tumkur in Karnataka to Gundlupet in Tamil Nadu.
- It passes through cities like Mandya and Mysore.
- NH 206 covers a distance of approximately 246 kilometers.

7. National Highway 219 (NH 219):
- NH 219 connects Kargil in Jammu and Kashmir to Pathankot in Punjab.
- It passes through cities like Jammu and Srinagar.
- NH 219 covers a distance of approximately 524 kilometers.

Therefore, a total of 7 national highways were merged to form National Highway 44 (NH 44).