Winchester was heavily fortified by forts and lunettes circumferencing the town, as well as along the outlying turnpike routes entering town.
Within Winchester, Milroy constructed or improved ten defensive fortifications, numbered Battery No.
1 through Battery No.
10, making improvements on many pre-existing forts and fortifications left by prior Confederate and Federal occupations.
The fortifications were linked in places with roads and trenches, and the use of these were a key to Milroy's defensive strategy.
Through a combination of retreating his forces into the defensive works, and then using his long-range heavy artillery, Milroy felt that he could hold out for weeks (if not months) against any force that may be thrown against him.

During the battle, Milroy concentrated his forces on the ridges west of town in his three highest and most improved forts connected by trenches.
The larger forts were named:
Battery No.
2 - Fort Milroy: Originally built by Confederate troops and called the "fortification on the heights" or the "Main Fort", this was improved under Maj.
Gen. Banks and called "Fort Garibaldi" by the 39th New York regiment.
The fort was improved extensively by Milroy's troops and held 14 guns, including heavy artillery, and renamed Fort Milroy (but then renamed Fort Jackson after the battle).

Battery No.
3 - Star Fort: This fort was built by Federal troops in 1862, improved by Milroy, and equipped with 8 guns.
 (Renamed Fort Alabama).

Battery No.
5 - West Fort: This was a 4-gun lunette located due west of Fort Milroy (later renamed Louisiana Heights)
The lesser fortifications initially used, but abandoned by Milroy during the course of the battle were:
Battery No.
1: A linear entrenchment-lunette along Bower's Hill south of Fort Milroy (Battery 2).

Battery No.
4: A large star lunette with entrenchments and minor lunettes containing 6 guns, located due north of Star Fort (Battery 3) along the same ridge line (north of modern VA 37).

Battery No.
6: A small lunette with 2 guns on a hill peak located in between West Fort (Battery 5) and Battery 7 (modern exit of VA 37 onto VA 522).

Battery No.
7: A large lunette and trench line with 8 guns on Apple Pie Ridge west of Apple Pie Ridge Road (modern James Wood High School).

Battery No.
8: A grouping of two redans downhill west of Star Fort (Battery 3).

Battery No.
9: Unknown location.

Battery No.
10: this was the Confederate Fort Collier built on the east side of the Martinsburg turnpike on the north end of town.

Fortification at Opequon Crossing (Parkins Mill Battery): A lunette or redan 4 miles south of Winchester at the Opequon River crossing on the Front Royal turnpike (modern VA 522).

For further information see:The Occupation of Major General Robert Milroy
Winchester was heavily fortified by forts and lunettes circumferencing the town, as well as along the outlying turnpike routes entering town. Within Winchester, Milroy constructed or improved ten defensive fortifications, numbered Battery No. 1 through Battery No. 10, making improvements on many pre-existing forts and fortifications left by prior Confederate and Federal occupations. The fortifications were linked in places with roads and trenches, and the use of these were a key to Milroy's defensive strategy. Through a combination of retreating his forces into the defensive works, and then using his long-range heavy artillery, Milroy felt that he could hold out for weeks (if not months) against any force that may be thrown against him.
During the battle, Milroy concentrated his forces on the ridges west of town in his three highest and most improved forts connected by trenches. The larger forts were named:
Battery No. 2 - Fort Milroy: Originally built by Confederate troops and called the "fortification on the heights" or the "Main Fort", this was improved under Maj. Gen. Banks and called "Fort Garibaldi" by the 39th New York regiment. The fort was improved extensively by Milroy's troops and held 14 guns, including heavy artillery, and renamed Fort Milroy (but then renamed Fort Jackson after the battle).
Battery No. 3 - Star Fort: This fort was built by Federal troops in 1862, improved by Milroy, and equipped with 8 guns.  (Renamed Fort Alabama).
Battery No. 5 - West Fort: This was a 4-gun lunette located due west of Fort Milroy (later renamed Louisiana Heights)
The lesser fortifications initially used, but abandoned by Milroy during the course of the battle were:
Battery No. 1: A linear entrenchment-lunette along Bower's Hill south of Fort Milroy (Battery 2).
Battery No. 4: A large star lunette with entrenchments and minor lunettes containing 6 guns, located due north of Star Fort (Battery 3) along the same ridge line (north of modern VA 37).
Battery No. 6: A small lunette with 2 guns on a hill peak located in between West Fort (Battery 5) and Battery 7 (modern exit of VA 37 onto VA 522).
Battery No. 7: A large lunette and trench line with 8 guns on Apple Pie Ridge west of Apple Pie Ridge Road (modern James Wood High School).
Battery No. 8: A grouping of two redans downhill west of Star Fort (Battery 3).
Battery No. 9: Unknown location.
Battery No. 10: this was the Confederate Fort Collier built on the east side of the Martinsburg turnpike on the north end of town.
Fortification at Opequon Crossing (Parkins Mill Battery): A lunette or redan 4 miles south of Winchester at the Opequon River crossing on the Front Royal turnpike (modern VA 522).
For further information see:The Occupation of Major General Robert Milroy
Second Battle of Winchester