The Allied plan for the advance of the main thrust of the 5th U.S. Army divisions, comprising the II and IV Corps, towards Bologna and the Po Valley required control of the main communication routes to Bologna and the adjacent dominant ridges.
- State Road 64, along which the Reno River flows and which connects the city of Pistoia to the western outskirts of the Emilian city.
- State Road 610, along which the Santerno River flows. It crosses the Giogo Pass and reaches Imola, a city located about 32 km southeast of Bologna, via State Road 9 (Via Emilia).
- State Road 65, which descends from the upper Tuscan-Emilian Apennines between State Roads 64 and 610 and reaches Bologna on its southern outskirts.

In the sector of the 8th British Army, the Gothic Line front line was broken through in Romagna on 1 September 1944. After a few days, the advance lost momentum, only to regain strength and culminate in the Battle of Rimini between 17 and 21 September 1944. Fighting continued along State Road 9, the Via Emilia of Roman Empire times, until the end of December, when the divisions reached the Senio River line.

During the same period, divisions of the II US Army Corps, to the east of the valley crossed by State Road 64, and the XIII British Corps of the 5th Army, attacked the German defence lines at Giogo di Scarperia on 12 September 1944; at Monte Battaglia on 27 September; at the vertical rock massif of Livergnano on 10 October; and at Monte Cerere and Monte Grande on 20 October. Between 10 September and 26 October, the four US divisions in the area suffered more than 15,000 casualties, including deaths and injuries. The 88th Division alone lost more than 5,000 men.

The divisions of the IV US Army Corps were deployed to the west of the valley crossed by State Road 64 and the Reno River in the upper Bolognese Apennines.
On 5 November 1944, units of the 1st Brazilian Infantry Division (F.E.B.) entrenched themselves below Monte Castello in the municipality of Gaggio Montano, just east of Monte Belvedere — a stronghold defended by the German 232nd Infantry Division. The first Brazilian assault on Monte Castello's defences, on the night of 28–29 November, resulted in 190 casualties, including dead, wounded and missing soldiers. A second attack on 12 December resulted in a further 250 casualties.
On 24 November 1944, three infantry battalions of Task Force 45 and around 200 partisans, backed by medium and light tanks, tank destroyers and artillery, attacked Monte Belvedere. The 2nd Battalion of the 370th Regiment of the 92nd Infantry Division, a battalion of the 1st Infantry Division of the Brazilian Expeditionary Force and the 435th Anti-Aircraft Battalion (reclassified as infantry) briefly gained the summit. However, they were forced to retreat due to accurate artillery fire from the rear, guided by German observers on the ridge which dominated the battlefield from the south. This ridge would later be named 'Riva Ridge' by the 10th Mountain Division of the US Army, who arrived on the front line in January 1945.

On 13 November, General Alexander issued a radio proclamation announcing the suspension of the offensive across the entire Gothic Line front.

Following the setback of winter 1944–45, the British 8th Army consolidated its positions on the Senio River, while the US 5th Army entrenched the II Corps on Monte Battaglia, Monte Cerere, Livergnano and Monterumici, extending to Monte Sole on the east bank of the Reno River. The IV Corps was positioned on the west bank, covering the area from Bombiana to Gaggio Montano, Porretta Terme, Castelluccio and Lizzano in Belvedere, as well as the Sestaione Cutigliano region.

The disposition of the opposing armies in December 1944 was as follows:

ORDER OF BATTLE OF THE 15TH ALLIED ARMY GROUP - 16 December 1944

Under the command of the Fifteenth Army Group was the Friuli Combat Group.

5th US ARMY
Under Army Command:
The 92nd Infantry Division is under army command in the Tuscany and Liguria coast sectors.

The II US Army Corps (positioned between the Sillaro valley and the SS 64).
The 1st US Armored Division is in Army Corps Reserve.
The 85th US Infantry Division was also under Army Corps Reserve.
34th US Infantry Division
88th US Infantry Division
91st US Infantry Division

IV US Army Corps (from SS 64, east of Bagni di Lucca).
10th US Mountain Division (from January 1945).
1st Brazilian Infantry Division
6th South African Armoured Division
2nd US Armoured Group
Task Force 45

13th British Army Corps (from the Senio Valley to the Sillaro Valley):
The 1st British Infantry Division and the 19th Indian Infantry Brigade.
6th British Armoured Division
8th Indian Infantry Division
78th British Infantry Division
1st Canadian Armoured Brigade

8th BRITISH ARMY 
Under army command:
1st British Armoured Division (Army Corps reserve).
2nd British Armoured Brigade
25th Tank Brigade (minus one regiment)
- 26th Armoured Brigade (minus two regiments transferred to the 6th British Armoured Division).
- 10th British Army Corps (army reserve in the Macerata area).
- 46th British Division (only two brigades).
Cremona Combat Group

1st Canadian Army Corps (Adriatic Coast).
1st Canadian Infantry Division
5th Canadian Armoured Division
9th British Armoured Brigade
21st British Tank Brigade

5th British Army Corps (across the Via Emilia)
2nd New Zealand Infantry Division
10th Indian Infantry Division (four brigades).
56th British Infantry Division (two brigades).
7th British Armoured Brigade
43rd Indian Gurkha Infantry Brigade

The 2nd Polish Army Corps was positioned south of the S.S. 9 Via Emilia.
3rd Carpathian Infantry Division
5th Kresowa Infantry Division (army corps reserve).
2nd Polish Armoured Brigade

GERMAN ORDER OF BATTLE of Army Group "C" - 31 December 1944
Under the command of Army Group
162nd Infantry Division (in the area south of Piacenza).
XCVII Army Corps (in north-eastern Italy)
188th Mountain Division (reserve)
237th Infantry Division
155th Division (in the field)
710th Infantry Division

X ARMY
Army Reserve (in the Bologna area).
26th Panzer Division
98th Infantry Division
305th Infantry Division
157th Mountain Infantry Division

LXXIII Army Corps (from the Adriatic coast to Bagnacavallo).
114th Jäger Division
16th SS Panzer Grenadier Division
356th Infantry Division

LXXVI Panzer Corps (south of S.S. 9, from Bagnacavallo)
278th Infantry Division
29th Panzer Grenadier Division
90th Panzer Grenadier Division

XIV Panzer Corps (operating from the south of Faenza to the Idice Valley).
715th Infantry Division
334th Infantry Division

I Parachute Army Corps (from the Idice Valley to the SS64)
1st Parachute Division
42nd Jäger Division
362nd Infantry Division
65th Infantry Division
4th Parachute Division
94th Infantry Division

XIV ARMY
LI Mountain Corps (advancing from S.S. 64 towards the northern Tyrrhenian coast).
232nd Infantry Division
148th Infantry Division
Monte Rosa Infantry Division
Italia Infantry Division

LIGURIA ARMY
Lombardy Army Corps (Gulf of Genoa)
135th Fortress Brigade
San Marco Infantry Division

LXXV Army Corps (on the France–Italy border)
34th Infantry Division
5th Mountain Division
Littorio Infantry Division

UNDER THE COMMAND OF THE SS AND THE POLICE.
XMAS Division
1st Italian SS Division
24th SS Mountain Division Karstwehr
Various Italian, Slovak and Czech militias were stationed beyond the Po River towards Lake Garda.

Bibliography:
Ernest F. Fisher, Cassino to the Alps (1989). 1989. 
W. G. F. Jackson, The Battle for Italy. 1967.
Fifth Army History, Part VIII.