diff --git a/gtsam/nonlinear/DoglegOptimizer.h b/gtsam/nonlinear/DoglegOptimizer.h
index 010a51fe7..51b03201b 100644
--- a/gtsam/nonlinear/DoglegOptimizer.h
+++ b/gtsam/nonlinear/DoglegOptimizer.h
@@ -133,12 +133,18 @@ public:
    */
   virtual void iterate();
 
-  /** Access the parameters */
+  /** Read-only access the parameters */
   const DoglegParams& params() const { return params_; }
 
-  /** Access the last state */
+  /** Read/write access the parameters. */
+  DoglegParams& params() { return params_; }
+
+  /** Read-only access the last state */
   const DoglegState& state() const { return state_; }
 
+  /** Read/write access the last state. When modifying the state, the error, etc. must be consistent before calling iterate() */
+  DoglegState& state() { return state_; }
+
   /** Access the current trust region radius Delta */
   double getDelta() const { return state_.Delta; }
 
diff --git a/gtsam/nonlinear/GaussNewtonOptimizer.h b/gtsam/nonlinear/GaussNewtonOptimizer.h
index 270182fbf..9c610b2b8 100644
--- a/gtsam/nonlinear/GaussNewtonOptimizer.h
+++ b/gtsam/nonlinear/GaussNewtonOptimizer.h
@@ -88,12 +88,18 @@ public:
    */
   virtual void iterate();
 
-  /** Access the parameters */
+  /** Read-only access the parameters */
   const GaussNewtonParams& params() const { return params_; }
 
-  /** Access the last state */
+  /** Read/write access the parameters. */
+  GaussNewtonParams& params() { return params_; }
+
+  /** Read-only access the last state */
   const GaussNewtonState& state() const { return state_; }
 
+  /** Read/write access the last state. When modifying the state, the error, etc. must be consistent before calling iterate() */
+  GaussNewtonState& state() { return state_; }
+
   /// @}
 
 protected:
diff --git a/gtsam/nonlinear/LevenbergMarquardtOptimizer.h b/gtsam/nonlinear/LevenbergMarquardtOptimizer.h
index 7f08db366..140bd247a 100644
--- a/gtsam/nonlinear/LevenbergMarquardtOptimizer.h
+++ b/gtsam/nonlinear/LevenbergMarquardtOptimizer.h
@@ -150,12 +150,18 @@ public:
    */
   virtual void iterate();
 
-  /** Access the parameters */
+  /** Read-only access the parameters */
   const LevenbergMarquardtParams& params() const { return params_; }
 
-  /** Access the last state */
+  /** Read/write access the parameters */
+  LevenbergMarquardtParams& params() { return params_; }
+
+  /** Read-only access the last state */
   const LevenbergMarquardtState& state() const { return state_; }
 
+  /** Read/write access the last state. When modifying the state, the error, etc. must be consistent before calling iterate() */
+  LevenbergMarquardtState& state() { return state_; }
+
   /// @}
 
 protected: