The onset of magnetoconvection in an inclined porous layer is investigated. The effects of physical parameters, such as the Rayleigh number, the inclination angle, and the Hartmann number, are examined. The system becomes more stable by increasing the inclination angle and Hartmann number. It is noted that the transverse rolls are more stable than the longitudinal rolls. A comparison between the linear and nonlinear instability analysis is discussed in more detail. The threshold values for the longitudinal and transverse rolls provide the subcritical instability region. It is noted that the subcritical instability region increases as the inclination angle also increases, whereas it remains unchanged as the Hartmann number increases. Besides, an artificial neural network (ANN) model using the Levenberg‐Marquardt backpropagation algorithm is employed to predict the distribution of critical Rayleigh numbers for both linear and nonlinear stability analyses. The optimal number of neurons in the hidden layer is selected on the basis of coefficient of determination, root mean square error, and root mean relative error. The simulated critical Rayleigh numbers obtained by the numerical study and the predicted critical Rayleigh numbers by the ANN coincides.