Elladan and Elrohir
 

after the council of elrond scouts were sent to gather news, including elronds sons who it is said went down silverlode and then to a strange country, but wouldnt speak of their errand to any besides elrond.is it known where they went and why?

Lorien to see their grandmother Galadriel I reckon .

but why would that be a secret?

As far as I remember it was not widely known that there still lived Elves in Lórien, it had become a mythical and even feared place, and - like the three Rings - was not a topic for every day talk.

I'm not sure why it was such a secret even in Rivendell that was still populated by the Elves, but, as all the old and wise people used to say, no-one should be trusted while dealing with the affairs of the Dark Lord because his spies can be anywhere.

i think so too
 

good reply agnazir am with u on this

In addition...
 

Aganzir is correct with his statement,

"'It is long since any of my own folk journeyed hither back to the land whence we wandered in ages long ago,' said Legolas, 'but we hear that Lórien is not yet deserted, for there is a secret power here that holds evil from the land. Nevertheless its folk are seldom seen, and maybe they dwell now deep in the woods and far from the northern border.'" - (Chapter 6, Lothlórien)

(However this is not really related to the thread, as the brothers originated from Rivendell.)

I surmise that it would be through Lothlórien that the brothers passed, in order to give word to Celeborn and Galadriel of the Fellowship's coming, it was their task at first to scout ahead and prepare the way for the Fellowship.

Perhaps it was this errand that they kept secret.

"2951- Sauron sends three of the Nazgûl to reoccupy Dol Guldur." - (Appendix B, The Tale of Years)

The reoccupation may have required them to journey into the lands known as the Brownlands, south of Dul Guldur. With three Nazgul in its vicinity at times, I think that sufficiently important to send ahead scouts to watch for any movement. As Aganzir has said, "his spies could be everywhere".

The discovery of the Fellowship would have been of grave misfortune.

yeah yeah..it's right.

I think also another reason for such needed secrecy was for the safety of Rivendell.

Most of the Elves were leaving, and eventhough Rivendell had some formidable warriors, it wasn't a place that could muster up an army like in Lorien or Mirkwood. Rivendell was more of a refuge and a safe haven for people to go and get Council. It was a hidden place for refuge, not a place right out in the open that could gather an army and stop assaults. It's remained secrecy was a must.

It was founded by Elrond as a place where the remaining Noldor retreated to and could go to and created as a refuge.

We also see times where Elrond has to go to other places to muster up an army, as Rivendell just doesn't have the people:
The safety of Rivendell was dependent on it's secrecy to the Enemy, it wasn't a military powerhouse (though it was a place with several good warriors) that could withstand continuous assaults. So, I'm thinking that Elrond didn't want to risk the secrecy being lost, as Rivendell simply didn't have the manpower (err...Elven power) to withstand attacks if it's exact location was found out.