Historically, criminal justice and law enforcement in Medieval cities and towns was extremely complex. The cities usually had overlapping jurisdictions reflecting the feudal boundaries within the town, not to mention ecclesiastical jurisdictions. For example, universities usually had the right to exclude city officials from the university grounds, nobles were exempt from municipal jurisdiction, and clerics were only subject to the jurisdiction of canon courts. This patchwork of law enforcement can make for a rich roleplaying adventure, but it doesn’t work too well when the city guard gets involved in an adventure as a speed bump or as a combat encounter.

One solution is to establish a city guard for each power center (p. 137 DMG) in the town. Another solution is to have a single force of city guards, but to allow power centers or holders of specific titles to command (or assign the command) of a certain number of squads of the guard. However you choose to structure the city guard in your campaign, here are some stat blocks to fill out the command structure.

Name, male human War1: CR ½; Medium Humanoid; HD 1d8+3 (7 hp); Init +0; Spd 20 ft.; AC 16 (+4 scale mail, +2 large shield); Atks +2 melee (+1 base, +1 weapon focus); or + 1 ranged (+1 base); Damage morning star 1d8, light crossbow 1d8; SA none; SQ none; AL LN; SV Fort + 2, Ref +0, Will +0; Str 11 Dex 11 Con 11 Int 11 Wis 11 Cha 11
Skills: Swim +1, Climb +1, Intimidate +2, Spot +2, Listen +2.
Feats: weapon focus (morning star), toughness
Gear: scale armor, large shield, morning star, light crossbow, 30 bolts, sap.

Sergeants (A sergeant will accompany from 5 to 10 guardsmen):
Name, male human War3: CR 2; Medium Humanoid; HD 3d8+3 (15 hp); Init +0; Spd 20 ft.; AC 18 (+6 splint mail, +2 large shield); Atks +4 melee (+3 base, +1 weapon focus); or + 3 ranged (+3 base); Damage morning star 1d8, light crossbow 1d8; SA none; SQ none; AL LN; SV Fort + 3, Ref +1, Will +1; Str 11 Dex 11 Con 11 Int 11 Wis 11 Cha 11
Skills: Swim +1, Climb +1, Intimidate +2, Spot +2, Listen +2, Gather Information +2.
Feats: weapon focus (morning star), toughness
Gear: splint mail, large shield, morning star, light crossbow, 30 bolts, sap.

Lieutenants (command 2 sergeants, 10-20 guardsmen):
Name, male human War5: CR 4; Medium Humanoid; HD 5d8+3 (23 hp); Init +4 (improved initiative); Spd 20 ft.; AC 19 (+7 half plate, +2 large shield); Atks +6 melee (+5 base, +1 weapon focus); or + 5 ranged (+5 base); Damage longsword 1d8, light crossbow 1d8; SA none; SQ none; AL LN; SV Fort + 4, Ref +1, Will +1; Str 11 Dex 11 Con 11 Int 11 Wis 11 Cha 12
Skills: Swim +1, Climb +3, Intimidate +3, Spot +2, Listen +2, Gather Information +2.
Feats: weapon focus (longsword), toughness, improved initiative
Gear: half-plate armor, large shield, longsword, light crossbow, 30 bolts, sap.

These units reflect the superior training of guardsmen in towns and cities

Line Troopers
male human Ftr1: CR 1; Size M; HD 1d10+1+3; hp 9; Init +1 (+1 Dex); Spd 20ft (base 30, -10 scale mail); AC 17 (+1 Dex, +4 scale mail, +2 shield); Attack +3 (+1 Base, +2 Str) melee, or +2 (+1 Base, +1 Dex) ranged; SV Fort +3 (+2 Base, +1 Con), Ref +1 (+0 Base, +1 Dex), Will +2 (+0 Base, +2 Wis); AL LN; Str 14, Dex 13, Con 13, Int 11, Wis 14, Cha 12.
Skills: Climb +2 (+2 Rank, +2 Str), Diplomacy +3 (+2 Rank, +1 Cha), Hide +1 (+1 Dex), Intimidate (+2 Rank, +1 Cha), Listen +2 (+2 Wis), Move silently +1 (+1 Dex), Spot +2 (+2 Wis), Swim +4 (+2 Rank, +2 Str);
Feats: Toughness, Power attack, Dodge.
Gear: Scale mail, large wooden shield, morning star, sap, light crossbow, 40 bolts, signal whistle.

Sergeants (per five guardsmen)
male human Ftr3: CR 3; Size M; HD 3d10+3+3; hp 26; Init +5 (+1 Dex, +4 Improved Initiative); Spd 20 ft. (base 30, -10 banded mail); AC 19 (+1 Dex, +6 banded mail, +2 shield); Attack +7 (+3 Base, +2 Str, +1 weapon focus, +1 masterwork weapon) melee, or +4 (+3 Base, +1 Dex) ranged; SV Fort +4 (+3 Base, +1 Con), Ref +2 (+1 Base, +1 Dex), Will +3 (+1 Base, +2 Wis); AL LN; Str 14, Dex 13, Con 13, Int 11, Wis 14, Cha 12.
Skills: Climb +2 (+2 Rank, +2 Str), Diplomacy +3 (+2 Rank, +1 Cha), Hide +1 (+1 Dex), Intimidate (+2 Rank, +1 Cha), Listen +2 (+2 Wis), Move silently +1 (+1 Dex), Spot +4 (+2 Rank, +2 Wis), Swim +4 (+2 Rank, +2 Str);
Feats: Toughness, Power attack, Dodge, Improved Initiative, Weapon Focus (morning star).
Gear: Banded mail, large wooden shield, masterwork morning star, sap, light crossbow, 40 bolts, signal whistle, potion of cure light wounds.

Lieutenants (per two sergeants)
male human Ftr5: CR 5; Size M (5 ft., 3 in. tall); HD 5d10+10; hp 46; Init +6 (+2 Dex, +4 Improved initiative); Spd 30 ft.; AC 12 (+2 Dex); Attack +7 (+5 Base, +2 Str) melee, or +7 (+5 Base, +2 Dex) ranged; SV Fort +6 (+4 Base, +2 Con), Ref +3 (+1 Base, +2 Dex), Will +2 (+1 Base, +1 Wis); AL LN; Str 15, Dex 14, Con 14, Int 12, Wis 13, Cha 8.
Languages Spoken: Common, Dwarven.
Skills and feats: Bluff +2 (+3 Rank, -1 Cha), Forgery +1.5 (+0.5 Rank, +1 Int), Hide +4.5 (+2.5 Rank, +2 Dex), Innuendo +4.5 (+3.5 Rank, +1 Wis), Intimidate +1.5 (+2.5 Rank, -1 Cha), Intuit direction +2.5 (+1.5 Rank, +1 Wis), Knowledge +4.5 (+3.5 Rank, +1 Int), Listen +1 (+1 Wis), Move silently +2 (+2 Dex), Spot +1 (+1 Wis); Blind-fight, Combat reflexes, Improved initiative, Power attack, Toughness, Two-weapon fighting.
Gear: Banded mail, large steel shield, masterwork morning star, sap, light crossbow, 40 bolts, signal whistle, potion of cure moderate wounds. One magic item from the following list: amulet of natural armor +1, boots of striding and springing, morning star +1, potion of see invisibility.

Thanks to Jamis Buck for the NPC generator used as a seed for many of these stat blocks.