West Yorkshire topped the table.
As usual, the North had some of the highest figures.
Lancashire featured in the top 10 counties of the number of complaints investigated - coming sixth with figures of 4,811 in 2015, compared to 5,252 the previous year. Greater London was top with 11,050 compared to 12,202.
The RSPCA revealed that dogs were the most persecuted pet in the North and across England and Wales. Almost 57 per cent of complaints investigated by the RSPCA, related to dogs. This compares to 24 per cent which related to cats - the second most abused pet.
Of Lancashire’s 4,811 complaints, 2,909 involved dogs; 1,085 cats; and 817 other.
Last autumn, an appeal was launched to find the culprits after four kittens were found dead with their skulls smashed in in Chorley. It was the second incident of its kind in just weeks.
Coun Paul Walmsley, responsible for enforcement of animal cruelty at Chorley Council, said: “These acts of cruelty are some of the worse we have seen in a long time.”
In another incident, a Jack Russell was left in a ‘terrible state’ by his owner Lucy Jo Dudley, as a debilitating skin condition caused his skin to peel away in places. Dudley, 39, was banned from keeping dogs for five years by Blackpool magistrates after she admitted to causing suffering to the animal.
Overall across England and Wales, there was 143,004 complaints of animal cruelty investigated in 2015, down from 159,831 in 2014.
Cases which had to be resolved by way of prosecution also fell. A total of 796 people were convicted of animal welfare offences in 2015, compared to 1,029 in 2014.
Dermot Murphy, assistant director for the RSPCA Inspectorate, said: “People think of dogs as man’s best friend but these statistics tell a different story. They are by far the most abused animal in this country and we investigate more complaints related to them than any other species.”
On the rise in 2015 was the number of owners who were offered and accepted animal welfare advice - 81,475 across England and Wales. In 2000 this figure was around 4,000, in 2002 around 50,000 and in 2007 around 78,000.